Peel and wash the potatoes before cutting them into thin slices.

Heat a frying pan with plenty of extra virgin olive oil. Add the potatoes and a little salt (and the onions thinly chopped lengthwise, if desired).

Remove the potatoes when they start turning golden brown. Place them in a large strainer to drain off the extra virgin olive oil and set aside in a colander or a plate over a paper towel.

Cut half the Manzanilla olives into slices. Set aside the rest for the end of the recipe.

In a separate bowl, beat the eggs, then add the sliced Manzanilla olives, potatoes (and onion if used). Mix well and add salt to taste.

Return the pan to the heat and add two tablespoons of extra virgin olive oil.

Add the egg mix, Manzanilla olives and potatoes, and lower the heat. Move the pan in a circular motion to keep the tortilla moving and prevent it from sticking. Flip the tortilla when it begins to bubble, with the help of a flat plate or lid.

Once the tortilla is ready, place it on a plate and cut into triangular pieces to serve.