2 lb. frozen hash browns
1 pt. sour cream
8 oz. shredded Mozzarella cheese
1 can cream of chicken soup
1/2 c. melted butter
1 c. chopped onion

Mix all ingredients in a large bowl and place in a lightly greased 9x13 inch glass baking dish. Bake uncovered at 375 degrees for 1 hour.