1. Put the olive oil in a large, deep-sided, ovenproof frying pan (preferably non-stick), add the potatoes, and cook at a gentle simmer for about 15 minutes, or until they are tender. Remove the potatoes with a slotted spoon and put them in a large bowl to cool.

2. Tip most of the oil out of the pan, add the onions and a pinch of salt. Cook over low heat until soft and beginning to brown. Add to the potatoes and leave to cool.

3. Whisk the eggs with a fork, then pour into the cooled potato and onion mixture, season with salt and pepper, and combine gently so all the potatoes get coated.

4. Preheat the oven to 400°F (200°C). Heat the 1 tbsp of olive oil in the frying pan until hot, then carefully slide in the egg mixture, spreading it evenly so it covers the bottom of the pan. Reduce the heat to medium-low and cook for 6–10 minutes, or until almost set.

5. Put in the oven, and cook for a further 10 minutes, or until set and golden. Alternatively, cook one side, then invert onto a plate and add back to the pan to cook the other side. Remove from the pan, leave to cool and set, then slice into wedges. Serve warm or cold.