Dice and cook enough potatoes to fill a casserole dish, 9"x13"; drain well. Add:

8 oz. sour cream
1/2 c. chopped onion (fine)
1 tsp. pepper
1 tsp. salt
10 oz. grated cheddar cheese
1/2 c. melted butter
1 can cream of chicken soup

Mix well and put in casserole dish. Bake 35 minutes at 350 degrees. Remove from oven, top with 1 cup corn flakes and 1/2 cup more butter. Pour over corn flakes and bake a few minutes longer.