Start by gently melting the butter in the microwave (a small microwave-safe dish works perfectly to prevent splatters).
Place the peeled and deveined shrimp in a medium bowl, then pour the warm melted butter over them.
Toss gently to coat the shrimp evenly—this helps infuse them with that rich, garlicky flavor base right from the start.
Next, add the white wine to the butter-coated shrimp—we like to use a good drinking wine here (just 3 tablespoons total for the whole recipe).Our golden rule for cooking with wine: if it’s something we’d happily sip on its own, it’s perfect for the dish. We never reach for a cheap “cooking wine”—a decent bottle truly elevates the flavor without overpowering it. (The small amount of wine cooks off completely in the oven, leaving behind a wonderful depth and brightness.) Next, stir in the minced garlic to the buttery shrimp mixture—it’s the star that gives this scampi its irresistible aromatic punch!Feel free to use convenient jarred minced garlic for speed, or go fresh for that extra vibrant flavor: simply peel the cloves with a handy silicone garlic peeler and press them through a garlic mincer. Either way works beautifully. Next, stir in the freshly chopped parsley and thyme leaves—these bright, aromatic herbs bring a wonderful freshness and elevate the entire dish.If you don’t have fresh herbs on hand, dried parsley and thyme work just fine! Just remember the standard conversion: dried herbs are more concentrated, so use about one-third the amount called for. (The general rule is a 3:1 ratio—1 teaspoon dried equals 1 tablespoon fresh.) Gently toss the shrimp with the butter, wine, garlic, and herbs until everything is evenly combined and the shrimp are beautifully coated in that flavorful mixture.
Next, slice the zucchini and yellow summer squash into thin, even rounds—a mandoline slicer makes this quick and uniform (just be careful with those sharp blades!). If you don’t have one, a sharp knife works too.
Prepare 6 sheets of aluminum foil, each about 15 inches long.
On each sheet, stack 6–7 slices of yellow squash and 6–7 slices of zucchini (alternating layers or as desired for even cooking). Season generously with salt and freshly ground black pepper
Divide the shrimp scampi mixture evenly among the 6 foil packets, placing about 1/6th (roughly a generous handful) on top of the vegetable stack in each.
Top each shrimp and vegetable stack with 1 lemon slice and 1 sprig of fresh rosemary.
Fold the sides of each foil sheet upward and crimp them together, then fold down tightly to create a secure seal along the top. Next, fold up the ends and crimp them tightly to fully enclose the packet.
Place the sealed packets on a baking sheet and bake in a preheated 400°F oven for 15–20 minutes, or until the shrimp is fully cooked (opaque and pink) and the vegetables are tender.
Carefully remove the foil packets from the oven (use oven mitts, as they will be very hot)
Open each packet cautiously, allowing the steam to escape away from you to avoid burns—the contents will be extremely hot and steamy.
Serve directly in the foil packets for easy cleanup. If preferred, gently transfer the contents to plates using a spatula, then spoon the flavorful juices from the packet over the shrimp and vegetables.