Classic tortilla

Slice the potatoes about ½cm thick. Heat 3cm olive oil in a large frying pan and add the onions. Cook gently for about 10 minutes until they start to soften, then add the potatoes and a couple of really good pinches of salt to the pan and keep cooking on a low heat, turning carefully now and again for another 20-30 minutes until the potatoes are completely tender. Try not to get too much colour on anything – you want them to stew in the oil rather than crisp up. Don’t worry if they start to break up a little.

Beat the eggs with some seasoning. Tip the cooked onions and potatoes into a colander or sieve over a bowl and drain. Tip them into the egg while still hot and give everything a really good stir.

Heat 2 tbsp of the drained oil in a small non-stick frying pan (about 20cm). You can use a larger pan but the tortilla won’t be as thick and it will be harder to turn.

Tip the egg mix into the frying pan and cook again on a gentle heat for 6-8 minutes until the bottom and sides are set and have come away from the pan.

Put a plate over the top of the pan, invert the tortilla onto it then slide it back, uncooked-side down. Cook for another 3-4 minutes until the bottom is set and light golden. Slide out onto a plate and serve just warm or at room temperature.