Spanish tortilla

Peel the potatoes and cut them into thin 3 mm slices. Slice the onion into thin half-moons.

Heat the oil in a 24 cm frying pan over medium heat, add the potatoes and onion and season with salt. Cook, stirring now and then, until the potatoes are soft but not browned.

The potatoes should gently poach in the oil, not fry: keep the heat medium-low, or they will crisp outside and stay hard inside.

Crack the eggs into a large bowl, add a pinch of salt and beat with a fork until smooth.

Drain the potatoes and onion in a sieve set over a bowl and save the oil. Fold the warm potatoes into the eggs and let stand for 5 minutes.

Heat 2 tbsp of the saved oil in the pan, pour in the egg mixture and level it. Cook over medium-low heat, tucking in the edges with a spatula, until the bottom has set.

Cover the pan with a flat plate wider than the pan, flip it in one quick motion, then slide the tortilla back into the pan. Cook for another 3–4 minutes until the centre is firm.

Flip over the sink wearing oven mitts: hot oil can run out from under the plate.

Slide the tortilla onto a board, let it rest for 5 minutes and cut into wedges. Serve warm or cold. Enjoy!

Strain the leftover oil and reuse it for frying — it picks up a lovely potato and onion flavour.