Heat the olive oil in a 20cm non-stick frying pan over a moderate heat, add the potatoes and onion and fry for a few minutes. Put the lid on, leaving a little gap for steam to escape, and reduce the heat a little. Let the potatoes and onion cook gently for 25 minutes, stirring every 5 minutes or so. Add the chorizo and cook for a further 5 minutes.
Remove the pan from the heat and lift out the potatoes, onion and chorizo with a slotted spoon. Pour all but a couple of tablespoonfuls of the oil into a jug and return the potatoes, onion and chorizo to the pan, off the heat. Lightly beat the eggs in a bowl, then pour over the potatoes. Add the parsley and plenty of salt and pepper, and stir well. Return the pan to the heat and turn the heat up slightly. Use a spatula to shape the tortilla, easing the top edge away from the side of the pan a little.
When the egg is almost set, take the pan off the heat. Invert a plate (one that is pretty much the same size as the tortilla) on top of it. Turn the pan and plate over together and lift the pan away, leaving the tortilla on the plate. Slide it off the plate back into the pan, cooked side up and let it rest off the heat for a few minutes to allow the base to cook a little in the residual heat of the pan.
Turn the tortilla out onto the plate again and allow to cool slightly and firm up for 10 minutes before serving.
Subscribe to our newsletter.