1. Peel and cut the potatoes, as well as the onion and bell pepper; put everything in a bowl and add salt.
2. Heat a good amount of oil in a pan (about one centimeter deep). Drain the water that the potatoes have formed and pour everything into the hot oil.
3. Cook for 10 minutes over medium heat, stirring occasionally.
4. Beat the eggs in a bowl. Drain the potatoes, bell pepper, and onion, and mix them with the eggs. Pour out the remaining olive oil in the pan, leaving about one tablespoon to cook the omelette.
5. Reheat the pan and pour the mixture into the hot oil.
6. Wait for 5 minutes and slide the omelette onto a plate. Flip it by placing the pan on top of the plate and flipping it quickly. Cook for 5 minutes on the other side.
7. Enjoy hot or cold.