Peel the potato, then cut it into ⅛-inch dice (about 1½ cups); rinse and dry. Put the oil in a 10- or 12-inch skillet and turn the heat to high. A minute later, add the potatoes, along with salt and pepper to taste, and turn the heat to medium-high. At first the potatoes will stick together, but as you stir and shake the pan occasionally, they will separate as they brown.</