Mix together sour cream & soup. Add salt, pepper, onion, cheese, & margarine. Add hash browns, making sure they are broken up. Put in a greased 9 x 13 pan (I use a glass pan). If you wish, mix 2 cups crushed corn flakes and 1/4 Celsius melted margarine and put on top of potatoes. Bake 1 hour in 350 oven.