Peel potatoes and chuck, boil until tender. When potatoes are about done, start the gravy. Heat the butter in a medium skillet over medium heat. Whisk in the flour, salt and pepper ( you may need a little more salt or less, according to your taste buds ) until smooth. Cook and stir over medium heat until browned, about 10 minutes. Gradually stir in milk so that no lumps form, and continue cooking and stirring until thickened. If the gravy becomes too thick, you may thin it with a little more milk.