01 - Preheat oven to 375°F. Grease a 9x13-inch casserole dish with butter or cooking spray.
02 - Cook egg noodles according to package instructions until al dente. Drain thoroughly and set aside.
03 - Melt 2 tablespoons butter in a large skillet over medium heat. Add chopped onion and minced garlic, sautéing for 3-4 minutes until softened and fragrant.
04 - Add frozen peas and carrots to the skillet. Cook for an additional 3 minutes, stirring occasionally.
05 - In a large mixing bowl, combine cooked noodles, shredded chicken, sautéed vegetable mixture, cream of chicken soup, sour cream, milk, cheddar cheese, dried thyme, salt, and black pepper. Stir until evenly combined.
06 - Spread the noodle and chicken mixture evenly into the prepared 9x13-inch casserole dish.
07 - In a separate bowl, combine panko breadcrumbs, melted butter, grated Parmesan cheese, and fresh parsley. Mix until the breadcrumbs are evenly coated.
08 - Sprinkle the crumble mixture evenly over the casserole surface, covering completely.
09 - Bake for 30-35 minutes until the topping is golden brown and the casserole is bubbling around the edges.
10 - Remove from oven and allow casserole to rest for 5 minutes before serving.