Ingredients
Potatoes (amount as desired; Russet are ideal),
2 litres/quarts cold tap water (for simmering),
Vinegar (amount as used in the original recipe; typically 1–2 tbsp),
Salt (for simmering water and for finishing),
Oil for frying (enough to fill pot 3 cm / 1.2" deep; peanut, canola, or similar high-heat oil).
Instructions
Peel the potatoes and cut into 6 mm / 1/4" French fries using a serrated knife. Keep cut fries submerged in a bowl of water to prevent browning while you cut the rest.
Transfer the potatoes to a colander and rinse under tap water for 15–20 seconds.
Place the fries in a large pot with 2 litres/quarts of cold tap water, vinegar, and salt. Bring to a boil over high heat, then immediately reduce to low so the surface is rippling gently, not boiling hard. Cook for 10 minutes, then carefully remove with a slotted spoon into a colander rather than tipping the pot, as the fries will break.
Spread the fries on 2 tea-towel-lined trays and leave to steam-dry for 5 minutes.
Pour 3 cm / 1.2" of oil into a pot at least 10 cm / 4" high, keeping at least 7 cm / 3" clearance between the oil surface and the rim for safety. Separate the fries into 3 batches.
For the first fry (blanching), heat the oil to 205°C / 400°F over medium-high heat. Lower a third of Batch 1 into the oil using a slotted spoon, wait 10 seconds, add another third, wait 10 seconds, then add the rest of the batch. Fry for 50 seconds, moving the fries around once or twice, then remove with a slotted spoon onto 2 paper-towel-lined trays in a single layer. The fries will still be white and floppy at this stage. Repeat this process with Batches 2 and 3, making sure the oil returns to 205°C / 400°F before each one.
Let the fries cool for 30 minutes, and line a large bowl with paper towels for draining and tossing later.
For the second fry (crisping), heat the oil back to 205°C / 400°F. Fry half the fries for 4 minutes, moving them around twice, until golden brown and crispy, then drain in the lined bowl. Repeat with the remaining fries.
Sprinkle with salt or your seasoning of choice, toss, and serve.
