Preparing the potatoes and onion
The potatoes are peeled and sliced into thin rounds. The onion is peeled and finely chopped. In a large frying pan, the olive oil is heated over medium heat, then the potatoes and onion are added. They are cooked gently, stirring regularly to prevent them from browning too quickly, until they are tender and lightly browned. Salt and pepper are added to taste.
Preparing the eggs
The eggs are beaten in a large bowl with a pinch of salt and pepper. Once the potatoes and onion are cooked, they are drained to remove excess oil and then added to the beaten eggs. The mixture is gently stirred to coat the potatoes and onion well.
Cooking the tortilla
In a lightly oiled skillet, pour the egg, potato, and onion mixture. Cook over medium-low heat to allow the inside to cook without burning the outside. After 5 to 7 minutes, when the bottom is golden brown, flip the tortilla using a plate or lid to cook the other side. The total cooking time is approximately 10 to 12 minutes, until the eggs are set but still slightly runny in the center.
