Classic Tortilla de Patatas with Sweet Onion

⏱ 50 min · Serves 4

Golden, custardy potato and onion tortilla with a barely-set middle — the kind you'd find on a bar counter in Madrid. Slow-poaching the potatoes in olive oil is the whole secret, and yes, you can strain and reuse that oil.

Per serving: 425 kcal · 13.5g protein · 29.0g carbs · 28.0g fat

Ingredients

• 600g waxy potatoes (such as Charlotte or Yukon Gold), peeled
• 1 large onion (about 200g), thinly sliced
• 300ml mild olive oil, for poaching
• 6 large eggs
• 1 tsp fine sea salt, plus extra
• Pinch of black pepper

Method

1. Slice the peeled potatoes into thin rounds, about 3mm thick. Pat them dry with a tea towel and toss with 1/2 tsp salt.
2. Heat the olive oil in a 22–24cm non-stick frying pan over medium-low heat. Add the potatoes and onion — the oil should just cover them and barely bubble, not fry.
3. Poach gently for 20–25 minutes, stirring occasionally with a slotted spoon, until the potatoes are completely tender and break easily when pressed. They should stay pale, not browned.
4. Tip the potatoes and onion into a colander set over a bowl to drain, saving the oil. Let them cool for 5 minutes.
5. Beat the eggs in a large bowl with the remaining 1/2 tsp salt and the pepper. Stir in the warm potatoes and onion, crushing a few slices lightly. Leave to sit for 10 minutes so the potatoes soak up the egg.
6. Wipe the pan, return 1 tbsp of the reserved oil and set over medium heat. Pour in the mixture, spread it level, and cook for 4–5 minutes, drawing the edges in with a spatula, until the base is set and golden.
7. Slide the tortilla onto a large plate, invert the pan over it, and flip confidently. Return to the heat and cook 3–4 minutes more for a just-set, slightly runny centre (5–6 minutes if you prefer it firm).
8. Slide onto a plate, rest 5 minutes, and serve warm or at room temperature, cut into wedges, with a little extra sea salt and crusty bread.