SERVES 4 2 pounds russet (baking) potatoes (about 4 large), peeled and cut into ¼-inch-thick fries (keep in a bowl of water until ready to cook) 2 tablespoons distilled white vinegar Kosher salt 2 quarts peanut oil Place the potatoes and vinegar in a medium saucepan, add 2 quarts water and 2 tablespoons salt, and bring to a boil over high heat Boil until the potatoes are fully tender but not falling apart, about 10 minutes Drain and spread them on a paper-towel-lined rimmed baking sheet Allow to dry for at least 5 minutes Meanwhile, heat the oil to 400°F in a Dutch oven or large wok over high heat Add one-third of the fries to the hot oil (the oil temperature should drop to around 360°F) and cook for exactly 50 seconds, agitating the potatoes occasionally with a wire-mesh spider, then transfer to a second paper-towel-lined rimmed baking sheet Repeat with the remaining potatoes (working in two more batches), allowing the oil to return to 400°F before each addition Allow the potatoes to cool to room temperature, at least 30 minutes; set the pot of oil aside The potatoes can be kept at room temperature for up to 4 hours or, for the best results, frozen in a single layer at least overnight Then, for longer storage, transfer to a zipper-lock freezer bag Return the oil to 400°F over high heat Fry half of the potatoes until crisp and light golden brown, about 3½ minutes, adjusting the heat as necessary to maintain the oil at around 360°F Transfer the potatoes to a bowl lined with paper towels to drain and immediately season with salt The cooked fries can be kept hot and crisp on a wire rack set on a baking sheet in a 200°F oven while you cook the second batch Serve immediately ... one-third of the fries to the hot oil (the oil temperature should drop to around 360°F) and cook for exactly 50 seconds, agitating the potatoes occasionally with a wire-mesh spider, then transfer to a... with the remaining potatoes (working in two more batches), allowing the oil to return to 400°F before each addition Allow the potatoes to cool to room temperature, at least 30 minutes; set the. .. Return the oil to 400°F over high heat Fry half of the potatoes until crisp and light golden brown, about 3½ minutes, adjusting the heat as necessary to maintain the oil at around 360°F Transfer the potatoes to a bowl lined