Stir together well the diced onion, sour cream, grated cheese, thinly sliced butter, and cream of chicken soup.  Add hash browns and mix well.

Spread mixture evenly in a 9 x 12 casserole dish and top with crushed corn flakes (can substitute potato chips).

Bake at 350 degrees F for one to one-and-a-half hours.

8 to 12 servings

You can use shredded hash browns or the cut potatoes like frozen potatoes O'Brien, but I think the shredded works best.  THis is a standard at any family gathering we have!