Heat plenty of olive oil in a skillet. Add 1 onion, finely chopped. Cook for 5 minutes.
Add 5 medium potatoes diced into small 1 cm cubes or chips. Cook for 20 minutes, or until the potatoes are tender.
Beat 4 eggs in a bowl and add salt to taste.
Drain potatoes and add them to the bowl with the whisked eggs. Clean out skillet.
Add 1 tablespoon of olive oil to skillet and fry tortilla for 15 minutes on very low heat. Flip tortilla over to a plate. Clean skillet again and add 1 tablespoon of olive oil. Fry the other side for 15 minutes.