Tortilla de patatas (Spanish Potato Omelette)

Preheat the oven to 200 °C. Peel the potatoes and onion, then slice them into pieces about 3 mm thick. Spread them out on a baking tray lined with baking paper (make sure the slices don't overlap too much), drizzle with a little oil, sprinkle with half a teaspoon of salt, and bake for 15 minutes.

Crack the eggs into a bowl, add the remaining salt and ground pepper, then whisk them. Add the baked potatoes and onion, then gently fold them together.

Heat one tablespoon of oil in a non-stick pan. Once hot enough, pour in the egg mixture and cook for 4 minutes. Then, place a plate over the pan, and with a firm movement, flip it over so the tortilla lands on the plate. Slide it back into the pan to cook the other side. The cooking time depends on the thickness of the tortilla (for this recipe, we used a 22 cm diameter pan). The tortilla is ready when it's springy when pressed; if it's completely hard, there's a risk it will be dry.