Hash Brown Ham Casserole

16 oz. sour cream
1 can condensed cream of chicken soup, 10.75 oz
1 pkg. froze loose pack hash brown potatoes, 32 oz
2 cups cubed cooked ham
8 oz. cubed American cheese
1/4 cup chopped onion, optional
2 cups crushed cornflakes
1/3 cup butter or margarine, melted
1 cup shredded mozzarella cheese, 4 oz

Preheat oven to 350. In large mixing bowl, mix sour cream and soup. Stir in froze potatoes, ham, American cheese and, if desired, onion. Transfer to 3 quart rectangular baking dish. Spread mixture evenly. Mix cornflakes and melted butter. Sprinkle over potato mixture. Bake, uncovered for 30 minutes. Sprinkle with mozzarella cheese. Bake for 20 to 25 minutes more or until bubbly around edges and heated through. Makes 8 to 10 servings.

To make ahead: Prepare as directed up until right before baking. Cover and chill for 8 to 24 hours. Sprinkle with cornflakes mixture. Bake for 50 to 55 minutes. Sprinkle with mozzarella cheese. Continue baking as directed.