Peel the Potato (3) and then cut them in half, then into quarters. Then, Slice the potatoes so that they are approx. 1cm thick. If they are too thin, they will over cook and if they are too thick, they will undercook, so this part is very important!
Once the Potatoes have been sliced, sprinkle with Salt (to taste).
Warm (not too hot!) up a pan with a large amount of Extra-Virgin Olive Oil (to taste). Add the Sliced Potatoes to the oil and leave to simmer for up to 5 minutes.
Thinly slice the Onion (1).
Add the Sliced Onion to the pan. Leave the Potato and Onion to cook through until they start to soften, around 20 minutes.
In a separate mixing bowl, whisk Egg (5) with some Salt (to taste).
Drain the oil out of the potato onion mixture using a colander. Let it sit in the colander for a few minutes to cool off.
Add the Potato Onion Mixture into the bowl with the Whisked Eggs and mix well
Heat up a pan and add the egg, onion and potato mixture, then stir a bit to mix. Even out the top with your spatula and ensure the edges are not stuck to the side of the pan by slightly sliding the spatula down and around the whole tortilla. Let this cook for 10 minutes.
Transfer the omelette onto a serving dish, and enjoy!