large mixing bowl, combine sauteed onion, 32 oz. frozen hash brown potatoes, 10 3/4 oz. cream of chicken soup, 8 oz. Cheez Whiz, and 8 oz. sour cream. Add salt and pepper to taste Mix thoroughly with a large spoon. Melt 1/2 stick margarine, and add 2 cups cornflakes. Heat the cornflakes, until they are crispy and the margarine is absorbed. Do not over-brown the cornflakes! Spray a 13-inch by 9-inch by 2-inch Pyrex dish (or similar oven-proof dish) with cooking oil spray. Spoon the ...