My sister found this one on the internet.

Hashbrown Casserole
2 pounds frozen shredded hashbrowns
16 oz. sour cream
1 can cream of chicken soup
1/2 cup butter or margarine
1/2 cup chopped onion
2 cups shredded sharp cheddar cheese

Preheat oven to 350 degrees. Spray 9×13 casserole with Pam. Spread potatoes in dish and season with salt and pepper. Melt butter and combine with undiluted soup, sour cream and onions in mixing bowl. Mix well, then pour mixture evenly over hashbrowns. Sprinkle cheese on top and bake approximately 45 minutes.