1. Place potatoes, onion and salt and pepper in greased 10x15 pan.
2. In saucepan mix Cheez Whiz, soup and sour cream and pour over potatoes.
3. Pour 1/2 butter over soup mix.
4. Sprinkle corn flakes then drizzle remaining butter.
5. Bake in 325 degree oven for 1 hour or until golden brown.
If you wish you can decrease the butter to 1 cup and the sour cream to 1/2 pint.