1 - Put a large non-stick frying pan on a low heat.

2 - Cook the onion slowly in the oil and butter until soft but not brown – this should take about 15 mins.

3 - Add the potatoes, cover the pan and cook for a further 15-20 mins, stirring occasionally to make sure they fry evenly.

4 - When the potatoes are soft and the onion is shiny, crush 2 garlic cloves and stir in, followed by the beaten eggs.

5 - Put the lid back on the pan and leave the tortilla to cook gently.