Presenting my Tapas Revolution book in 2013, the most sold Spanish cookery book in the UK

Peel and slice the potatoes into thin rounds.

Heat olive oil in a large skillet over medium heat until shimmering.

Add the sliced potatoes to the skillet and cook until tender, about 15-20 minutes.

If using, add sliced onion halfway through cooking the potatoes.

Drain the potatoes and onion from the oil and let cool slightly.

In a bowl, whisk the eggs and season with salt and black pepper.

Gently fold in the cooled potatoes and onion into the egg mixture.

Wipe the skillet clean and add a little olive oil over medium heat.

Pour the potato-egg mixture into the skillet and cook until the bottom is set, about 5-7 minutes.

Carefully flip the tortilla using a plate and cook the other side until golden, about 5-7 minutes.

Slide the tortilla onto a serving plate and let it cool slightly before slicing.

Serve warm or at room temperature.

Allergens