Classic Tortilla de patatas

Preheat the oven to 200 °C. Peel the potatoes and onion and cut them into slices about 3 mm thin. Spread the slices on a baking sheet lined with baking paper (making sure they don't overlap too much). Drizzle with a little oil, sprinkle with half of the salt, and bake in the oven for about 15 minutes.

Meanwhile, beat the eggs in a large bowl. Add the remaining salt and ground pepper and whisk everything well. Carefully mix the baked potatoes and onions into the egg mixture.

Heat a coated pan (ideally about 22 cm diameter) with one tablespoon of oil. Pour in the egg-potato mixture and let it set over medium heat for about 4 minutes. Once the bottom is golden brown, place a large plate on the pan, carefully flip the pan over, and turn the tortilla onto the plate. Then carefully slide the tortilla back into the pan to finish baking the other side. The tortilla is ready when it yields elastically to light pressure. Serve hot or at room temperature.