1 lg. bag hashbrowns
1 sm. bag hash browns
1 stick melted butter
1/2 c. chopped onion
1 bag chopped Cheddar cheese
Small sour cream
1 can cream of mushroom soup

Combine all ingredients together in a 9 x 13 inch casserole. Sprinkle more Cheddar cheese on top. Put in refrigerator overnight. Bake at 350 degrees for 45 minutes.