Peel the potatoes and wash them in very cold water.
Cut the potatoes (as explained above). Remember, for crispy fries, it’s very important that the slices have a wavy shape when cut with a knife or mandoline.
Place the sticks in a bowl with cold water and three tablespoons of white vinegar.
Dry them and place them in a pot of boiling water for 1 minute. This step removes excess starch from the potatoes and gives you a much smoother texture.
Take them out of the boiling water, rinse them under running cold water, and place them in a bowl of ice water. Before proceeding with the next step, the potatoes must be dried with absorbent paper towels.
Heat the oil in a frying pan over high heat and gradually add the potatoes, following the cooking method described above. For a crispier result, it’s advisable to use peanut oil or sunflower oil.