Chicken Spaghetti

8 oz. spaghetti, broken in half
1 can cream of mushroom soup
1/2 cup sour cream
1/4 cup milk
1/4 cup butter, melted, divided
1 tablespoon dried parsley flakes
1/4 teaspoon garlic powder
1/4 teaspoon salt
1/4 teaspoon pepper
1 cup shredded part-skim mozzarella cheese
1/2 cup grated Parmesan cheese
1 celery rib, chopped
1/2 small onion, chopped
1/2 of a 4 oz. can of mushroom stems and pieces, drained
2 cups cubed cooked chicken
1 cup crushed cornflakes

Cook spaghetti according to package directions; drain. In a large bowl, combine the soup, sour cream, milk, 2 tablespoons butter and seasonings. Add the cheeses, celery, onion and mushrooms. Stir in chicken and spaghetti.

Transfer to a greased square 8x8 or 9x9 baking dish. Combine cornflakes and remaining butter; sprinkle over top of casserole.

Bake, uncovered, at 350 degrees for 30-40 minutes or until bubbly.