Tortilla Española

Peel the potatoes and cut them in half lengthwise, then slice them into half-moons about 3 mm thick; thin, even slices cook at the same rate. Peel the onion, halve it and slice it thinly. Toss both together in a bowl with a good pinch of salt. Pat the potatoes dry with a clean cloth if they are wet, because water makes the oil spit.

• potato600 g
• onion1
• saltto taste

Heat 150 ml of olive oil in a 24 cm non-stick frying pan over medium-low heat. Add the potatoes and onion, which should be almost covered by the oil, and cook for 18–22 minutes, turning them gently every few minutes, until the potatoes are completely tender and break at the touch of a spoon. They should soften without browning. Drain in a sieve over a bowl, keeping the oil.

• potato600 g
• onion1
• olive oil150 mL

Beat the eggs in a large bowl with a pinch of salt until just combined, without making them frothy. Tip the warm potatoes and onion into the eggs and press them down so that they are covered. Leave the mixture to sit for at least 5 minutes. The potatoes absorb some of the egg, which binds the tortilla and keeps it soft and moist in the middle.

• egg6
• potato600 g
• onion1

Wipe out the pan and heat 2 tablespoons of the strained oil over medium heat. Pour in the mixture, smooth it and cook for 4–5 minutes, shaking the pan now and then, until the edges are set and the base is golden. Put a large flat plate over the pan, turn it over in one motion, slide the tortilla back in and cook for another 4–5 minutes, tucking in the edges.

• egg6
• olive oil30 mL

Slide the tortilla onto a plate and leave it to rest for at least 10 minutes. It continues to set from its own heat, and the centre should be just set and slightly juicy, not liquid. Cut it into wedges with a sharp knife. It is served warm or at room temperature, never straight from the pan.