2) Fill a large bowl with water, submerge the potatoes and soak for at between 30 minutes and 24 hours. This will help to remove the excess starch from the potatoes and keep them from oxidising.
3) Heat the oil to 160C in a deep fryer.
4) Remove the potatoes from the water and pat dry to remove the excess water. Add 2 handfuls of potatoes to the hot oil. There should be at least 2.5cm of oil above the potatoes.
5) Par cook for 5 to 7 minutes, until the potatoes are light brown. Sieve the potatoes, gently shaking off any excess oil and leave to drain on a wire rack. Repeat until all of the potatoes are par cooked.
6) Raise the oil temperature to 180C. Cook the potatoes again, 2 handfuls at a time, for about 2 minutes, until golden brown. Remove from the oil, shake off the excess oil, and season lightly in a bowl with salt and pepper. Repeat until all potatoes are cooked.