Use the simplest ingredients: really good fresh eggs and finely sliced cooked potatoes / Lisa Barber
Serves 6-8

This is a traditional tortilla, using the simplest ingredients: really good fresh eggs and finely sliced cooked potatoes. Using the same method you can add almost anything you like: finely chopped, hot and spicy chorizo, mushrooms or, during the summer months, sweet red peppers. But this simple and traditional version is my favourite. Try serving it with the braised oxtail.

100ml/31/2fl oz extra-virgin olive oil
1 yellow onion, peeled and chopped finely
1 clove of garlic, crushed
600g/11/4lb potatoes, peeled and sliced as finely as possible
10 organic, free-range eggs
Sea salt and freshly ground black pepper
A little extra olive oil for drizzling at the end

Place the oil in a large, heavy-based pan over a low to medium heat. Add the onion, garlic and a pinch of salt. Cook for five minutes, then add the sliced potatoes. Cook for 25 minutes over a low heat, stirring every now and then until the potatoes are soft and beginning to break up and almost falling apart.

Crack the eggs into a large bowl and whisk well. Season with salt and pepper, add the cooked potatoes to the egg mixture and stir well to combine. Heat a little more olive oil in the same pan in which you cooked the potatoes. Pour in the egg mixture.

As the eggs begin to thicken and set, shake the pan in a circular motion and shape the mixture into a flat, round disc. Cook for a further two minutes then place a large circular plate on top of the pan and invert the tortilla on to the plate. Gently slide the tortilla back into the pan – the cooked side should now be facing upward.

Place the tortilla over a low heat and cook for a further couple of minutes. When cooked, the tortilla should be set, but with just the slightest wobble. Carefully slide on to a plate and serve warm.