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 thoroughly and set aside.
03 - Heat a large skillet over medium heat with a splash of oil. Add onion, carrots, celery, and garlic; sauté for 4–5 minutes until softened and fragrant.
04 - In a large bowl, mix cooked vegetables, chicken, peas, cream of chicken soup, sour cream, milk, cheddar cheese, thyme, salt, and pepper. Add cooked noodles and fold gently until evenly combined.
05 - Spread the mixture evenly in the prepared baking dish, smoothing the top with a spatula.
06 - In a separate bowl, combine panko breadcrumbs, Parmesan cheese, melted butter, and parsley. Mix until all ingredients are evenly moistened.
07 - Sprinkle the crumble mixture evenly over the casserole. Bake uncovered for 30–35 minutes until topping is golden brown and edges are bubbling.
08 - Remove from oven and let rest for 5–10 minutes before serving to allow the casserole to set for easier scooping.