Using a mandolin or by hand, cut potatoes evenly.
Fill up a large bowl with cold water and add the potatoes, tossing them around to release the starch. Empty the bowl and refill it again with cold water; toss and refill one more time.
Transfer the bowl with cold water to the fridge and chill for 2 hours and up to 24 hours for extra-crispy fries.
Later on, drain the potatoes in a colander; let them sit for 15 minutes.
Place a clean towel on a cutting board and drop the potatoes on it. Using paper towels, pat the potatoes dry; set aside.
In a Dutch oven, heat oil until it reaches 300ºF.
Working in batches, blanch the fries for 2 to 4 minutes depending on the thickness.
Using a spider strainer or slotted spoon, remove the blanched potatoes and place them on a baking sheet lined with paper towels; let them cool while working with the others.
Increase the oil temperature to 375ºF.
Add blanched potatoes (the temperature will drop) and fry until golden brown, about 8 minutes.
Scoop the fries up and transfer them to a clean baking sheet lined with paper towels to absorb any excess oil.
Transfer the fries to a large bowl and season with salt to taste.