2 lbs. frozen, shredded hash browns
1/3 c. melted butter
3/4 c. chopped onion
1 can cream of mushroom soup
3 c. shredded Cheddar cheese
2 c. sour cream

Thaw potatoes; combine all ingredients. Bake in 9 x 12 inch cake pan at 350 degrees for 1 hour.