01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with cooking spray or butter.
02 - Cook egg noodles according to package directions until al dente. Drain well and set aside.
03 - Heat a splash of oil in a large skillet over medium heat. Add onion, carrots, celery, and garlic; sauté for 4-5 minutes until softened and fragrant.
04 - In a large bowl, mix sautéed vegetables, chicken, peas, cream of chicken soup, sour cream, milk, cheddar cheese, thyme, salt, and pepper. Add cooked noodles and fold gently until evenly coated.
05 - Transfer mixture to the prepared baking dish and spread into an even layer.
06 - In a separate bowl, combine panko breadcrumbs, Parmesan cheese, melted butter, and parsley. Mix until evenly moistened.
07 - Sprinkle crumble mixture evenly over the casserole surface.
08 - Bake uncovered for 30-35 minutes until the topping is golden brown and the filling is bubbling around the edges.
09 - Let the casserole rest for 5-10 minutes before serving to allow the filling to set.