Slice potatoes into ½ inch thick sticks, without removing the peel. Soak them in cold water for at least 1 hour, and up to overnight. This helps to get rid of the starch and gives you crispy fries as a result.
Rinse the potatoes with cold water and dry them really well on paper towels. You want to make sure that they are completely dry, or they will splatter when you add them to the frying oil.
Heat oil in a large dutch oven to 300°F/150°C. Fry the potatoes in batches for 5 minutes. Remove from the oil with a slotted spoon and drain on paper towels while you fry the other batches.
Increase the heat of the oil to 400°F/205°C and fry each batch of fries for 5 more minutes, or until they are golden brown and crispy but not too dark. With a slotted spoon, remove the fries from the oil and drain on a paper towel.
Sprinkle with salt and any other desired seasonings while the fries are still hot.