In my family we call this Hashbrown Casserole.
One 32 ounce package, hashbrowns
3/4 cup, butter, melted
1/2 cup, chopped onion
1 can, cream of chicken soup
8 ounces, sour cream
1 cup, shredded cheddar cheese
2 cups, corn flakes
Combine the hashbrowns, half a cup of the butter, the onion, soup, sour cream and the cheese in a bowl and blend well. Pour into a greased casserole dish. Crush corn flakes in a bowl and stir in remaining butter. Sprinkle this over the potato mixture and bake at 350° for 50 minutes.