Hash Brown Casserole

1 - 2 lb. bag hash browns, thawed
1/2 cup melted butter
1 can cream of mushroom soup
2 cups grated cheese
1 tsp. salt
1/4 tsp. pepper
1 - 8 oz. carton sour cream
1 grated onion
1 1/2 cups crushed corn flakes

Mix all ingredients except corn flakes and pour into a large, lightly greased casserole dish. 

Sprinkle top with the corn flakes and bake for 45 minutes at 350 degrees.

You can make this casserole ahead of time.  Simply freeze the casserole. 

When you are ready to make it, add the corn flakes to the thawed casserole and bake.