Best Squash Casserole with Green Chiles
Got extra yellow squash from the garden? This cheesy squash casserole is a total crowd-pleaser! Tender summer squash and onions mixed with sharp cheddar, parmesan, sour cream, and roasted green chiles, then topped with a golden breadcrumb-parmesan crust.
Looking for a crowd-pleasing summer side dish? This Summer Squash Casserole with Green Chiles is exactly what you need!
We’re pulling out all our favorite summer squash recipes right now to make the most of the garden bounty. This one is a standout — tender yellow squash and onions mixed with sharp cheddar, parmesan, sour cream, and roasted green chiles, finished with a golden breadcrumb-parmesan crust.
It’s creamy, crunchy, a little spicy, and totally delicious. Perfect for summer dinners, and it freezes beautifully so you can enjoy a taste of summer all year long! ✨
Turn those garden squash into something special with this flavorful casserole. One of our all-time favorites!
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This Summer Squash Casserole is an absolute showstopper! Loaded with tender yellow squash, sharp cheddar, and parmesan cheeses, plus a kick of roasted green chiles, it delivers the perfect blend of creamy and savory flavors.
The crowning glory? That irresistible golden breadcrumb-parmesan crumble on top that gives you the most satisfying crunch in every bite.
It’s truly out-of-this-world delicious — so good that even your picky eaters might come back for seconds (or thirds)! Whether you’re feeding the family or taking it to a summer gathering, this casserole is guaranteed to impress.
Try this drool-worthy squash casserole while your garden is overflowing with fresh squash. One bite and you’ll be thanking us later!
Summer Squash Casserole Recipe:
Ingredients:
- 6 medium squash, thinly sliced
- 1 large onion, thinly sliced
- ¼ cup Butter
- ½ cup Parmesan Cheese, grated
- 1 cup Sharp Cheddar Cheese, shedded
- ½ cup Sour Cream
- 3 whole roasted green chile, peeled and chopped
- ¼ teaspoon salt
- ¼ teaspoon black pepper
- Fresh Chopped Parsley, Optional
Topping Ingredients:
- ¼ cup Breadcrumbs
- ¼ cup Parmesan Cheese
- 1 Tablespoon Butter, melted
Equipment Needed:
- Cutting Board
- Sharp Knife
- Large Skillet
- Mixing Bowl
- 2 Quart Baking Dish
🥣 Recipe Tips for this Summer Squash Casserole with Green Chiles:
- Control the moisture for the best texture – Yellow squash releases a lot of water as it cooks. For a creamier, less watery casserole, you can lightly salt the sliced squash and let it sit for 10–15 minutes, then pat dry before sautéing. Or sauté the squash a little longer until some of the liquid evaporates. This helps the casserole set up nicely without becoming soggy.
- Customize the heat level – The roasted green chiles give this dish a delicious mild kick. If you have picky eaters or prefer less spice, use mild canned green chiles or reduce the amount. For more heat and authentic Southwest flavor, double the chiles, use Hatch green chiles, or add a pinch of cayenne to the filling.
- Make it ahead and freeze like a pro – This casserole freezes beautifully! Assemble it completely (including the topping), cover tightly, and freeze unbaked. When ready to use, thaw overnight in the fridge and bake as directed, adding 5–10 extra minutes. You can also bake it first, cool completely, then freeze for quick reheating later — perfect for busy winter nights or holiday meals.
How too make a Squash Casserole with Green Chiles:
- Begin by thinly slicing 6 medium yellow squash and 1 large yellow onion. Aim for about ¼-inch slices so the vegetables cook evenly and become perfectly tender.
- In a large skillet or wok, melt 3–4 tablespoons of butter over medium heat. Add the sliced squash and onions to the pan.
- Sauté them, stirring occasionally, for about 8–10 minutes until the onions turn soft and translucent and the squash is just becoming tender. You want them cooked but still slightly firm since they’ll continue baking later in the casserole.
- Transfer the cooked squash and onions into a large mixing bowl.
- Add the roasted green chiles, shredded sharp cheddar cheese, grated parmesan cheese, sour cream, salt, and black pepper.
- Gently fold everything together until the vegetables are evenly coated and the mixture is well combined. Be careful not to mash the squash — you want to keep some texture.
- Lightly grease a 2-quart baking dish with butter or cooking spray, then pour the squash mixture into the dish and spread it out evenly.
- In a small bowl, combine the remaining parmesan cheese, breadcrumbs, and 1 tablespoon of melted butter. Stir until the crumbs are moistened and crumbly.
- Sprinkle this breadcrumb-parmesan mixture generously over the top of the casserole for that perfect golden, crunchy crust.
- Preheat your oven to 350°F (175°C).
- Place the assembled casserole in the oven and bake uncovered for 20–25 minutes, or until the breadcrumb-parmesan topping is beautifully golden brown and crispy.
- Once done, carefully remove the dish from the oven and let it rest for 5–10 minutes. This allows the casserole to set up slightly, making it easier to serve while staying nice and creamy.
- Garnish with a sprinkle of fresh chopped parsley for a pop of color and brightness, if desired.
Can you freeze this Squash Casserole?
Yes you can! This squash casserole can be made ahead of time and refrigerated or frozen until ready to bake.
We’re making a big batch of these Summer Squash Casseroles right now and freezing several for later. We’re big fans of freezer meals, and having a delicious vegetable side dish ready to go in the freezer is such a treat during the cold winter months when the garden is resting.
Items that we use to freeze our squash casseroles
- Aluminum Pans with Lids
- Freezer Grade Plastic Wrap, optional
- Freezer Marking Pens
To freeze: Assemble the casserole in a freezer-safe dish, cover tightly with foil, and freeze before baking. When ready to enjoy, thaw overnight in the refrigerator and bake as directed (you may need to add 5–10 extra minutes). You can also bake it first, cool completely, then freeze for quick reheating later.
Just imagine pulling out a bubbling pan of this cheesy, green chile-spiked squash casserole on a chilly evening — it brings back all those fresh summer flavors! It pairs beautifully with holiday meals too. Serve it alongside your Thanksgiving turkey or with our favorite Christmas Baked Ham with Pineapple Glaze for an easy and impressive side dish.
Other Summer Squash Recipes:
🥣 Recipe
Equipment
- Cutting Board
- 2 quart baking dish
Ingredients
- 6 medium squash thinly sliced
- 1 large onion thinly sliced
- ¼ cup butter
- ½ cup parmesan cheese grated
- 1 cup sharp cheddar cheese shredded
- ½ cup sour cream
- 3 whole roasted green chile peeled and chopped
- ¼ tsp salt
- ¼ tsp black pepper
- Fresh chopped parsley optional
Topping
- 1/4 cup breadcrumbs
- 1/4 cup parmesan cheese
- 1 tbsp butter melted
Instructions
- Begin by thinly slicing 6 medium yellow squash and 1 large yellow onion. Aim for about ¼-inch slices so the vegetables cook evenly and become perfectly tender.
- In a large skillet or wok, melt 3–4 tablespoons of butter over medium heat. Add the sliced squash and onions to the pan.
- Sauté them, stirring occasionally, for about 8–10 minutes until the onions turn soft and translucent and the squash is just becoming tender. You want them cooked but still slightly firm since they’ll continue baking later in the casserole.
- Transfer the cooked squash and onions into a large mixing bowl.
- Add the roasted green chiles, shredded sharp cheddar cheese, grated parmesan cheese, sour cream, salt, and black pepper.
- Gently fold everything together until the vegetables are evenly coated and the mixture is well combined. Be careful not to mash the squash — you want to keep some texture.
- Lightly grease a 2-quart baking dish with butter or cooking spray, then pour the squash mixture into the dish and spread it out evenly.
- In a small bowl, combine the remaining parmesan cheese, breadcrumbs, and 1 tablespoon of melted butter. Stir until the crumbs are moistened and crumbly.
- Sprinkle this breadcrumb-parmesan mixture generously over the top of the casserole for that perfect golden, crunchy crust.
- Preheat your oven to 350°F (175°C).
- Place the assembled casserole in the oven and bake uncovered for 20–25 minutes, or until the breadcrumb-parmesan topping is beautifully golden brown and crispy.
- Once done, carefully remove the dish from the oven and let it rest for 5–10 minutes. This allows the casserole to set up slightly, making it easier to serve while staying nice and creamy.
- Garnish with a sprinkle of fresh chopped parsley for a pop of color and brightness, if desired.
Notes
Freezing Squash Casserole
What we use to freeze this casserole:- Aluminum Pans with Lids
- Freezer Grade Plastic Wrap
- Freezer Marking Pens
Nutrition
Click HERE to save this casserole with green chiles to Pinterest
The green chiles are a nice addition! Bring on the southwest flavors!
This is a keeper.
Hello old Friend! It’s so good to see you again, you know both of us love those green chiles in almost everything.
Very good, but how did you get 71 carbs, it seems really high when I look at ingredients.
The nutrition facts are automatically calculated within the Recipe Card. There are 8 servings and the only carbs of substance is the the 1/4 cup of bread crumbs and then of course the complex carbs of squash and onions. There are very little carbs in cheeses. But keep in mind sometimes the computations can be off a little but I believe this is pretty close.
I can’t wait to try this. We have a ton of squash! How would you freeze this? Before or after baking?
I would bake it before freezing. Then it’s just a matter of defrosting and heating up. Thanks so much for asking
This was very good , I have a bunch of red bell peppers and I got my hatch chili’s and I may try roasting a red bell with my chili’s and try that . Do you think it would be good ?
I bet it would be delicious, but it would have a different flavor. Please let us know how it turns out
This is delicious but I will try a shallow dish next time. I used a deep dish to bake it and the liquid from the vegetables sat at the bottom. Should have known better. The only change I made was using a small can of green chili’s I had on hand. Thank you for your recipe. : )
Oh thank you so much for your kind comments. So glad it worked for you and I didn’t think about using a more shallow dish, thanks for the update.
This sounds so good! Cannot wait to try! I notice in ingredients list butter for the topping is listed as 1 tsp. In the instructions butter is listed as 1 Tbsp. I am assuming it is the larger amount.
Oh you are so right, it’s supposed to be 1 TBSP. I’m correcting it now, thanks so much for letting me know.
This was so very good. I wasn’t about to roast any peppers but used a can of fire roasted green chili peppers – will use more next time. I’m pretty sure I sliced my squash thinner than shown in your photo as I used a mandolin. But they were perfect. Thank you for sharing this recipe.
Thank you so much for your sweet comments.
This was a hit at my house. I didn’t have any green chiles, so I used a cup of Trader Joe’s Hatch Chile salsa—medium. If there are people at your house that don’t like spicy food, I’d just use a can of mild chopped chiles. Next time, I’ll just put 1/2 to 1/3 cup of salsa. I almost set my husband’s taste buds on fire! Oops. Lol. I love this recipe, my old squash casserole recipe was getting a little too bland.
Oh this makes me so happy, thank you for your kind comments. Oh salsa does sound good in this also, great idea!
So I have a whole bunch of the scallop squash or some call them patty pan, do you think I could use these in the recipe instead? If not do you have a recipe using the patty pan squash?
I’m sure patty pan squash would be delicious in this. I have used other squash such as zucchini. And unfortunately I don’t have any recipes for patty pan squash but thanks for bringing it up, I need to share some.
This sounds so yummy. As a diabetic I have to be careful concerning carbs. Can you tell me where all the carbs come from in this recipe?
I am not well versed in diabetics so I’m not sure exactly what you need. But I’m assuming most of the carbs are from the squash but there are breadcrumbs in this recipe. If you are concerned please contact your doctor or health care official before trying it.
@Evelyn, something I do to cut carbs is replace the bread crumbs with finely ground pork rinds-the plain ones with salt only. Then I mix it half and half with Parmesan cheese. Either the real cheese or I have used the kind in the shaker with the green lid. Once I have ground them up either in food processor or vitamix I use this mixture instead of breadcrumbs and it lowers the carb count in recipes! And I use this in a zucchini casserole recipe that calls for making the casserole then putting this topping on at the end and putting it under a broiler for 3-5 min. It is delicious and crunchy on top. I would never know that it was such a mixture on top. It’s one of our favorite dishes. I will try your recipe but trade the topping to keep my carbs lower. Just trying to help and share ideas. I love yellow squash and I will try this. Thx!
I love it when someone adapts a recipe so they can enjoy while adhering to their diet restrictions. Thanks so much for sharing these tips
Very good casserole! Like others, I didn’t have green chiles on hand, so I used slivers of fresh red pepper. I also threw in some fresh basil that I had on the counter. And to answer one person’s question, I used patty pan squash. It was very nice in the casserole because it stayed firm instead of getting mushy. I like that the recipe uses a small amount of bread crumbs instead of Ritz crackers, which I’m not fond of.
Oh this is good to know. Thanks so much, it’s always great to hear about people’s variations to recipes.
Looking forward to trying this but one person’s medium squash is sometimes another person’s small or large. Can you tell us an approximate number of cups or weight of squash needed for this recipe?
I just googled it and 1 medium squash is around 1 cup to 1.25 cups. Hope this helps.
Thank you!
@Evelyn,
Hi, just found your site and I’m going to make this recipe (which looks amazing) for lunch.
I cook a lot by ingredient weight and found that 2 medium yellow (summer) squash weigh a pound. This may be helpful to others. My squash is starting to come in and I’m running to stay ahead of it!
Ah that is good to know. I haven’t ever weighed them so thanks so much for sharing.
Made this Monday night and it was so delicious! Thank you for the recipe! My large skillet was full to the top with unpeeled fresh summer squash. I used 3/4 can of mild chilli peppers (2 1/2″ can size) but next time I will use the entire can. I baked it in a 3 quart glass pan. This is a keeper recipe and I will share it with other summer squash growers?
Thank you so much for your kind comment, it makes my heart happy that you enjoyed it. Thanks so much for any and all sharing, we appreciate it so much.
My husband & I are New Mexican and have been have been for the past 55 years.. This is a great dish, and we will make again with a few adjustments.. First 3 green chilies are no where near enough .. second, we will use yellow onion not white( although you don’t specify) and 3rd we will use bread crumbs to thicken in the casserole itself but use panko seasoned as the topping, much crispier. I didn’t have enough parmesan so I did use a blend of parmesan and asiago cheese, not sure if it is a plus or minus.! Overall an excellent way to use summer yellow squash! We had supper tonight of both your yellow squash recipe and fried pattypan ( my first use)
Thanks for sharing !!
I lived in New Mexico for over 17 years and totally agree with you on adding more green chilies. HA! I did downsize it from my personal taste to accommodate those that don’t sleep, eat and dream of green Chilies like us. Love that you made it your own. Thanks so much for your kind comments
I used poblano peppers ant it turned out so so good! A nice change from sautéed squash or other squash side dishes!
Pueblo Poblano peppers I roasted along with zucchini – didn’t have any yellow squash at the moment. It was so so good!
That sounds great also. Thank you for letting us know you enjoyed this recipe.
So I saw the above comment about the amount of squash, my squash are all different sizes, so looking at your estimate of size the recipe would use 6-7 cups of squash? Thank you1.
This is the best dish with both zucchini and yellow quash. I fixed it as a side dish and it ended up being the main dish. Everyone loved it. Great dish.
That makes my heart happy. We are so glad you enjoyed it.
Chilies, can you use canned jalapeno? If using fresh is it Poblanos? can you use canned green chilies. Bread crumbs, can you use seasoned ready-made? how about Italian ready-made bread crumbs or panko. This recipe looks wonderful. I just want to make it perfect for thanksgiving.
The Chilies we refer to in this recipe are Hatch Green Chilies. Or some call them Anaheim Chilies or Big Green Chiles. And yes Yes Canned Green Chiles would be exactly what you would like to use. Jalapeños would not work but maybe Poblanos would. Any kind of bread crumbs would work in a pinch or even panko but sometimes Italian Seasoned bread crumbs clash with other flavors. Thank you so very much for your interest and we are sure you and your family will love this casserole. We have rave reviews on it. Hugs Evely
Very tasty! I am glad that i did not slice the squash thinly i prefer texture rather than mush! Seriously great combo-onions, squash and green chiles. I doubled the chiles amount in my dish. Just the perfect amount of cheese and sour cream. Its not gooey, cheesy or creamy. Keeps all the natural flavors intensly delish ! And the crust i used panko bread crumbs. I cooked it longer to get a nice brown on top.
Thank you so much for your kind comments! Next time I will have to try slicing it thicker.
Excellent..used 3 squash and 3 zucchini because that’s what I had..also use 2-7oz cans of diced fire roasted chilis as couldn’t find fresh locally..the only other thing I will do differently is double the topping..this was better than desert!!
We love this casserole! I freeze half , every time I make it , to save for winter
I added chicken to make it a whole meal and used Ritz crumbs instead of bread crumbs because I was out. Delish!
That a great substitution idea. Thanks for sharing
Unbelievably fantastic I could eat that until I pop.
Thank you very much!
Awe. Thanks so much!
Excellent dish! Used pepperjack cheese and it was yummy!
My family and I loved this recipe!! Delicious!!! Can’t wait to make it again! Thank you for sharing this recipe!!
Awe Thanks. We are so glad you enjoyed it.
My mouth is watering! Will make it tomorrow. Do you think using sautéed jalapeños could be substituted for the green chilies?
I bet Jalapeños would work if you like it a little more spicy. Sounds really good.
This was so good! Used diced canned green chilis. Everything else by the recipe. Yum!
Yay!! Soo happy you like it!
So good!! I did one can diced chilies, and roasted 2 poblanos and roasted the onion as well in my air fryer, per someone else’s comment. Made Chicken tacos and black beans as well in case this wasn’t a hit, (leftover chicken I had made so really simple) but neither my husband or I touch anything except for adding some black beans to this. I also doubled the breadcrumbs. I am still so uncomfortably full I ate so much!
So good to hear. This makes my heart happy! Love roasted peppers, all peppers.
Could this casserole be made ahead &baked later?
Yes it certainly could. In fact I have a couple of these casseroles in the freezer that I prepared when my garden was producing an abundance squash.
This is truley the Best, I could have eaten the whole thing by myself. A keeper
Awe thanks so much!
To hard to see recipe because of soooooo many ads.
I am so sorry you had this experience, I will notify my ad network. Also in the future you can hit the jump to recipe button and it will take you down above he recipe card. Then you can either read off the recipe card or print. Thank you for taking the time to let me know.
All I can say is Yum!!!
Thanks!!
All I can say is Yum!!!
Made this and added some corn. Came out delicious
This is our favorite squash casserole no other comes close to this culinary delight!
This is my 3rd time to make this this summer. I peel then thinly slice my overgrown yellow squash with my food processor and this makes a very trnder and delicious dish of what otherwise is an overwhelming squash. I have been sautéing, micing and baking it all in one large oven-safe skillet which makes this very easy.
This was an absolutely delicious recipe, and I made very few changes. I used two small cans fire roasted green chiles as I did not have access to fresh. I used Greek yogurt in place of sour cream because it’s what I had. And I removed quite a lot of the “juice” from the squash after sautéing with the onion, so the casserole wouldn’t be too wet. I know in doing that I was removing some serious flavor but the casserole turned out amazing. The whole table was dead quiet as everyone devoured it! I will be making this again!