2 lbs. frozen hash brown potatoes, thawed
12 oz. charp cheddar cheese, shredded
1 (16 oz.) tub sour cream
1 can cream of mushroom soup
1 stick margarine, melted
1/2 small onion, diced (optional)
Directions: Mix all together in a large bowl, then pour into a 13x9 inch greased pan. Bake at 375°F for 1 to 1-1/4 hours, or until golden brown.