Cut the potatoes into uneven, thin slices of different shapes and sizes. In a bowl, sprinkle a lot of salt over them and mix well.

Heat ½ cm of olive oil in a large frying pan. When it's very hot, add the potatoes. Add the onion after 5 minutes.

In a large bowl, break the eggs, beat them, add a pinch of salt and pepper.

Keep stirring the frying pan so the potatoes don’t turn brown or stick to the bottom of the pan. When they start breaking under the touch of the spoon, take the pan off the heat and use a slotted spoon to transfer the potatoes to the bowl with the beaten eggs. Drain the oil from the pan.

Mix the potato and egg well together while the pan gets very hot with no oil in it. Add the mix to the frying pan on medium heat and flatten it down with your spoon.

When the edges of the tortilla are cooked, slide it onto a plate then turn it over and back into the frying pan. Press down the edges to create a typical tortilla shape.

Take the tortilla off the heat when a knife put into it comes out clean (this should take less than a few minutes after the tortilla has been turned over).