Method

1. Scrape the potatoes or you could even leave the skin on, if preferred. Cut them into thick slices and add finely chopped onion.
2. Heat oil in a large frying pan, add the potatoes, onions and cook gently, keeping partially covered for 30 minutes, stirring occasionally until the potatoes are well softened. Strain the potatoes and onions through a colander into a large bowl (set the strained oil aside).
3. Beat eggs separately, and then stir into the potato-onion mixture with plenty of finely chopped parsley and salt & pepper to taste. Heat a little of the strained oil in a pan, tip the mixture into the pan and cook on a moderate heat while using a spatula to shape the omelet into a cushion.
4. When almost set, invert on to a plate and slide back into the pan to cook the other side for a few more minutes. Invert twice more, cooking the omelet briefly each time and pressing the edges to keep the cushion shape. Slide on to a plate and cool for 10 minutes before serving.