Add 3 tablespoons of the reserved oil back to the skillet. Heat the oil in the skillet over moderately high heat until very hot but not king (it must be hot or the eggs spreading the potatoes evenly around the will stick: add the potato and egg mixture. pan. Reduce the heat to low. and shake the pan often and run a spatula around the side approximately 8 to 10 and bottom to make sure the omelet is not sticking After minutes, when the omelet is cooked 3 of the way through top is no longer liquid) and the bottom is beginning to brown. place a large plate over the pan and invert the omelet onto the plate