Preheat oven to 350°. Lightly grease a 2-quart rectangular baking dish; set aside. In a very large bowl, combine soup, cheese, milk, sour cream, onion, and pepper. Stir in potatoes. Spread mixture evenly in prepared baking dish. Cover and bake for 45 minutes; stir potatoes. Sprinkle with cornflakes. Bake, uncovered, for 20 to 25 minutes more or until heated through and bubbly. Let stand for 10 minutes before serving.
This traditional family-favorite side dish has been lightened up with reduced-fat soup and cheese, fat-free milk, and light sour cream.