Step 1

Preheat the oven to 350 degrees F.

Step 2

Grease a 3-quart baking dish.

Step 3

Cook the spaghetti until al dente, according to the package directions.

Step 4

Drain the pasta.

Step 5

In a large bowl, combine the cream of chicken soup, the cream of mushroom soup, the sour cream, the milk, 2 tablespoons of the butter, the parsley, the garlic powder, the salt, and the pepper.

Step 6

Add the mozzarella cheese, the parmesan cheese, the celery, the onions, and the mushrooms.

Step 7

Stir in the chicken and the pasta.

Step 8

Transfer the pasta mixture to the prepared baking dish.

Step 9

Combine the cornflakes and the remaining butter.

Step 10

Sprinkle the cornflake-butter mixture over the top of the pasta mixture.

Step 11

Bake, uncovered, until bubbly, about 45-50 minutes.

Step 12

Serve hot.