Heat ½ cup (120 ml) of oil in a skillet over medium heat.
In a large saucepan or fryer, heat a large volume of oil to 300 F (150˚C).
Fry the potatoes for the first time for 7 to 8 minutes. Do not overload the pan or deep fryer. For 2 lb (1 kg) of potatoes, cook about ⅓ French fries at a time.
Just before serving, fry the French fries a second time in the oil heated to 375 F (190˚C) for about 3 minutes (they must be crisp without being hard). Season with salt.