1. Peel the potatoes then wash and dry. Cut in thin slices and fry slowly in a deep frying-pan containing oil at a medium-hot temperature.
2. Add the very finely-sliced onion and fry the potatoes and onion together until soft and beginning to turn golden. Stir occasionally with a slotted spoon, breaking up the ingredients as they soften.
3. After about ten minutes, drain off the oil.
4. In a bowl, beat the eggs with a little salt. Add the potato and onion mixture.
5. Return the frying-pan to the heat with a little of the oil used previously and turn the egg mixture into it. Cover and cook over a low heat for 5-10 minutes or until the base is golden. Using a large plate or lid, turn the omelet and return to the pan until the eggs set.

Serve either hot or cold on a round dish.

A great partnership can be set up between the potato omelet, probably Spain’s most emblematic dish, and a fruity, young Tempranillo red.