I am embarrassed to admit that despite having lived in Spain for over a year and a half now, I have only very recently attempted this dish.  Despite being an avid tortilla-lover, the idea of making this dish at home always intimidated me.  Until now, I have been generally content to eat it once a month at the Bodega de Ardosa, a wonderful old bar on Calle Colon where the owner’s mother makes a deliciously squidgy omelette every morning, but which very quickly sells out.

Fortunately, my good friend Sonia (who has quite a reputation for her tortilla de patata) took me aside in her kitchen one recent Sunday afternoon, and helped me make my very first one, and I can honestly say that it’s surprisingly easy.  The key is a good, non-stick pan (about 18-20 cm across, with high edges), fresh free range eggs, and good waxy potatoes.  The first time you flip a tortilla is a little terrifying, but it does get easier with practice.

The onion is controversial.  Some people like to add a thinly sliced onion when cooking the potatoes, and you will find that all Spaniards fall firmly into one of two camps – those that are adamant that a tortilla should never include onion, and those who believe it improves the flavour.  I made my first tortilla “sin cebolla” (without onion), and the second one “con cebolla” (with onion), and now I am hooked on the latter - the onion almost caramelises and imparts a lovely flavour.  Try it both ways and see what you prefer!

Spanish people generally use large, multi-purpose potatoes for their tortilla, but I have also made it with kipfler (fingerling) potatoes and it was delicious. Waxy potatoes are preferable to floury here.

Tortilla de patata

500 ml light olive oil
700 g potatoes, peeled and cut into thin, irregular slices (hold the potato in your hand while you slice it, being careful of course not to cut yourself) - once peeled you should have about 600g
1 large onion, peeled and very thinly sliced (optional)
5 free-range eggs
1 heaped teaspoon sea salt, plus extra to serve

Heat olive oil in a wok or deep frying pan, add onion (if using) and cook gently over medium-high heat for 8 minutes, stirring often.  Now add the potatoes, and keep stirring.  You do not want the potatoes or onion to brown – they just need to cook through and soften.

After about 15-20 minutes, when the potatoes and onions are very soft and starting to break up, drain them in a colander over a bowl.  You can then strain the oil and keep it in a jar to use for your next tortilla.

Break the eggs into a bowl and beat gently with a fork, then tip in the potato mixture and salt, and gently mix again.

Heat a tablespoon of the strained oil in a 20cm non-stick frying pan over medium heat, and a soon as it is hot add the egg mixture (your pan should be almost completely full).  Reduce the heat a little and cook for about 5-8 minutes, shaking the pan a little and using a plastic spatula to loosen the edges of the tortilla.

To flip the tortilla, place a large plate over the pan, and invert (over the sink is best), then quickly slide the tortilla back into the pan.  This is certainly the most nerve-wracking part of the process, and it can be a little messy, but it won’t affect the end result.  Continue cooking for another 3-5 minutes (shaking the pan in a circular motion from time to time) and then flip onto a plate once more and slide it back in the pan for a couple more minutes - flipping your tortilla a few times will give it nicely rounded edges.  Your tortilla should now be ready - it should feel almost set but still have a little wobble.  I like my tortilla a little bit oozy in the centre, but you can keep cooking it for a couple minutes longer if you want it to be completely set.

Allow to sit for at least 15 minutes, then serve warm or at room temperature, sprinkled with sea salt and with crusty bread on the side.  Tortilla should be eaten on the day it is made – both the texture and flavour suffer if it is refrigerated.  I like it best as a late breakfast, but it also makes a nice aperitivo in the afternoon with a glass of wine. 

It should serve four (though the 2 of us usually manage to eat the whole thing between us in one go).