1. Peel and chop the potatoes in circles of ½ cm thick approximately. 

2. Peel the onion and chop it in small pieces. 

3. Put the potatoes and the onion in the pan. It should be filled halfway. Cover with olive oil : all the potatoes must be bathed in oil. Then put a lid : the potatoes must be cooked both in oil and in steam. 

4. Once the potatoes are cooked (the point of a knife must be able to sink into them without difficulty), pour the olive oil into a container.

5. Put the potatoes and onion in a bowl. 

6. Add the beaten eggs. There must be enough eggs for the tortilla to be well bound.

7. Add salt and pepper. 

8. Mix gently (don’t do mashed potatoes !).

9. Add 2 to 3 mm of olive oil in the pan and put the mixture into it.

10. Cook one side of the tortilla over low heat. When the bottom is golden brown, flip the tortilla on a plate before sliding it in the pan on the uncooked side. It’s a delicate operation.

11. When both sides are browned, slide the tortilla into the plate.