A flat tortilla is almost identical to its Italian cousin, the frittata, but is generally thicker and therefore more rustic.
100 ml (scant 1 cup) olive oil
400g (14oz) Desirée potatoes, peeled and cubed
2 red onions, roughly chopped salt and freshly ground pepper
200g (7oz) chorizo sausage, skinned
1 garlic clove, crushed
2 tbsp chopped flat parsley leaves
6 eggs
Heat two-thirds of the olive oil in a frying pan, 20 – 22 cm (8–9in) in diameter and about 4 cm (1½in) deep. When it is hot, put in the potatoes and cook over a medium heat for 10 minutes. Add the onions, salt lightly, and continue to cook for another 10 minutes or so.
In the meantime, cut the chorizo into 2 mm (
in) slices. Add to the frying pan with the garlic and parsley. Mix well, without crushing the potatoes, and cook for another 2 minutes. Tip everything on to a plate and leave to cool slightly. Wipe out the frying pan with kitchen paper, ready for cooking the tortilla.
Lightly beat the eggs in a large bowl and season with salt and pepper. Heat the remaining olive oil in the frying pan. Using a spoon, mix the eggs delicately into the cooled potato mixture, then pour into the pan. Start cooking over a medium heat, stirring gently every few minutes with the side of a fork, as if making an omelette.
As soon as the eggs are half-cooked, stop stirring, and cook over a very low heat for 2 – 3 minutes, until the underside of the tortilla is almost cooked. Slide it on to a lightly oiled platter, then invert it back into the pan and cook for another 2 minutes, until both sides are cooked the same and the middle of the tortilla is still soft.
Slide the tortilla on to a plate and serve it whole or cut into wedges. It is equally good served hot, warm or at room temperature, but not chilled.