Turn oven on to 350F.
Peels and cut the potatoes into 1/2 inch thick cubes. Place in a large bowl of cold water until ready to drain and add to large pot of boiling water. Let cook for about 5 minutes. When you take a little cube out it should smoosh reluctantly when you push down on it with the back of a spoon. Drain immediately and rinse with cold water in a cullender.
In another large bowl add your cream of mushroom soup, ground black pepper, chopped green onion tops, milk and cheddar. Mix until incorperated.
Fold the cooked potatoes into the soup mixture with a spatula.
Pour mixture into an 8x 12x baking dish. Sprinkle corn flakes or smashed potato chips on top.
Bake for 45 minutes. If using corn flakes you might want to cover with tin foil for the first 25 minutes, and then uncover to let brown. Otherwise the flakes might get too brown and crunchy.
My family always used frozen hashbrowns. The country style "homefries". I prefer to do my own. It takes a little longer to boil the potatoes, but at least I know my potatoes will be done baking in 45 minutes and not 2 1/2 hours. Tit for Tat really.