- 2 lb Maris Piper potatoes; cut into long french-fry sticks, about 3/8x3/8 inches thick.
- Peel 2 lb. large russet potatoes; cut into long french-fry sticks, about 3/8x3/8 inches thick. Rinse; shake off water.
- Transfer potatoes to a large deep heavy pot, spreading potatoes so they\'re no more than 2 layers deep. Pour in safflower or vegetable oil to cover potatoes by 1\". Place pot over medium heat. Cook for 15 minutes (oil will begin bubbling gently). Continue cooking, occasionally loosening potatoes from the bottom of the pot with a heatproof spatula, until potatoes are very tender, 25–30 minutes more. Increase heat to medium-high and cook until golden and crisp, about 15 minutes longer (oil will bubble more vigorously).
- Using a slotted spoon, transfer fries to paper towels to drain. Season with coarse sea salt.