Prepare the vegetables

• Peel the potatoes, wash them and cut them into thin slices.
• Peel the onion and slice it thinly.

Fry the potatoes and onion

• Heat the olive oil in a frying pan over medium heat.
• Add the potato slices and onion, season with salt and cook gently until tender and lightly golden, without browning too much.

Drain

• Remove the potatoes and onion with a slotted spoon or colander and drain well, keeping a little oil in the pan.

Mix with the eggs

• Beat the eggs with salt in a mixing bowl.
• Add the drained potatoes and onion and stir to coat.
• Let the mixture rest so the potatoes absorb the egg.

Cook the tortilla

• Pour the mixture into the hot pan and cook over medium-low heat until the edges set and the bottom is golden.

Flip and finish

• Slide a plate over the pan, flip the tortilla and slide it back into the pan.
• Cook until set but still slightly moist in the centre.
• Rest a couple of minutes before serving.