2 lb. bag frozen hash browns, thawed
1 3/4 c. onion, chopped
1 can cream of mushroom soup
1 lb. sour cream
1 stick butter, melted
8 oz. grated cheddar cheese

Mix all ingredients. Spread into a 9 x 13 inch pan or dish. Bake at 375 degrees for 1 hour. Sprinkle top with extra grated cheese.