How to make
Prepare the first, larger tortilla by cutting the potatoes into relatively thin flakes of any size. Proceed in the same way with the onions. Add salt and stir.
In a pan with a diameter of 10″ (25 cm) heat oil over medium heat - the bottom should be one finger thick. Pour the vegetables and stir from time to time so that they can soften and fry evenly. This is necessary because the oil does not cover them and if we do not mix the bottom, they will be cooked on the bottom only. Once they have softened, the potatoes will crumble in places, but don't worry about that at all. We do not aim for them to remain intact or in the right shape.
As soon as they start to aquire an appetizing color, remove them from the heat and strain the fat, which we do not throw away. Leave it to cool, while beating the eggs with a little salt.
Place the pan back onto the heat with very little fat, the rest can be used for the second tortilla. Combine the potato mixture and the eggs and stir. Pour it into the pan, flatten it out well and leave it on a moderate heat until the edges start to turn white and slightly harden on top (3 minutes are enough for this purpose).
Place a lid or plate larger than the diameter of the pan and quickly turn the tortilla over, then gently slide it back into it and bake it for another 2 minutes on the other side. Here the most important thing is first- to have a quality pan with a non-stick bottom and second - to act really fast so that the egg does not get runny.
Set the cooked tortilla aside and prepare the other one - smaller, in the same way, using a pan with a diameter of 8.5″ (22 cm).
To assemble our beautiful appetizer, spread the larger one with mayonnaise, without reaching the edges. Arrange the green leaves and on them the tuna, which has been previously strained from the liquid and fat in the tin. Cover it with the smaller tortilla and serve it.
The Spaniards consider the best tortilla to be the one that is soft and with a slightly still runny egg inside (not raw, of course), so it is baked for a short time (2-3 minutes on both sides), although in this way, turning it will be more difficult and to hides risks.
For starters, I recommend the first time to try to cooking it on a slower heat, almost minimal and this it will harden and turning will be much easier. It will not be so tender, but little by little you will gain skills and with each one you will have a nicer and better tortilla.
Enjoy your meal!
*Arugula and baby spinach can be replaced with iceberg lettuce or other green salad leaves.
The Wonderful Double Tortilla Española with Stuffing is very tasty!