Preheat your oven to 350 degrees. Spray a 9x13 pan with non-stick cooking spray, set aside.
Boil bowtie pasta, according to package directions, until just al dente.
Meanwhile, in a large skillet, add ¼ cup of butter and heat over medium heat, until melted. Add frozen vegetables, and cook until just thawed.
Add 6 tbsp flour and mix well. Cook 1-2 minutes. Stir in milk, and bring mixture to a boil. Cook 4-5 minutes over medium heat, frequently stirring, until thickened.
Add cooked chicken or turkey, cream of chicken soups, sour cream, and salt and pepper (to taste, I prefer to be generous, this makes a big dish). Mix until well combined.
Add in cooked, drained pasta, and stir to combine.
Pour mixture into your 9x13 pan and cover with foil. Bake in the oven for 25 minutes, until casserole is thoroughly heated through.
Optional, top with shredded cheese and bake another 10-15 minutes, until cheese is melted.