The secret to making good french fries is to cook them twice: the first time to cook the potatoes through, the second time, at a higher temperature, to brown and crisp them. If you don't have a frying basket, quickly remove the fries from the oil with a large slotted spoon.
2 pounds unpeeled russet potatoes, cut lengthwise into 1/3-inch-thick sticks
About 8 cups vegetable oil, for frying
Fine sea salt
In a large bowl, cover the potatoes with water. In a deep fryer fitted with a basket or a heavy medium saucepan, heat 3 inches of vegetable oil to 340°. Drain the potatoes and pat dry with paper towels. Add half the potatoes to the oil and cook until they begin to blister and turn golden, about 15 minutes. Spread the fries on paper towels to drain and cool. Repeat with the remaining fries.
Heat the oil to 375°. Add a quarter of the fries and cook until browned and crisp, 1 to 2 minutes. Drain on paper towels and repeat with the remaining fries. Sprinkle with salt.