This recipe may seem a little long-winded, but it does produce THE best chips - golden crispy on the outside, light and fluffy on the inside.
The beauty of this method is that the potatoes can be cooked twice, then kept in the fridge for at least a week, before the final cooking. Or you can wait a day or two in between each of the cooking stages if you do not have the time to do it all at once.
As to which cooking fat to use, groundnut oil is probably the best, as it is very pure and odour-free. You could try rendered beef fat, and goose or duck fat would be delicious too. If you don't want to use rendered fat, the litre of groundnut oil will be sufficient for both the first and second frying processes.
1kg Potatoes for Chipping or Maris Piper, washed and peeled
1 litre groundnut (peanut) oil
1 litre rendered fat (optional)
1. Using a sharp kitchen knife, square off the potatoes into rectangles, then cut them into chips about 1cm thick. The length of the pieces is not so important, but you do want to keep them the same thickness, so that they cook at the same rate. Place them straight into a bowl under cold running water and keep them there for about 10 minutes to rinse off some of the starch.
2. Next, bring a large pan of unsalted water to the boil and plunge in the drained potatoes. Bring it back up to the boil and simmer gently for about 10 minutes, or until the point of a knife easily penetrates the chips. Make sure the water is only just simmering - if it boils too aggressively, the potatoes will begin to break up before they are cooked sufficiently.
3. Using a slotted spoon, lift the potatoes carefully out of the water and place them on a tray. Allow them to cool, then place in the fridge until cold. You will notice that the chips harden when chilled.
4. For the next stage, heat the groundnut oil in a deep-fat fryer to 130C/250F and plunge in the chips. After about 5 minutes, the chips will take on a drier appearance before colouring (do not let them brown). They have now finished their second cooking. Drain, let them cool to room temperature, then put in the fridge.
5. When cold, they are ready for their final cooking. If you are using rendered fat for this, heat it to 180C/350F. Alternatively, use the groundnut oil, heated to the same temperature. Plunge in the chips and cook until golden brown. This may take 8-10 minutes - you need to be patient in order to obtain a really crisp chip.
6. Drain and season with salt only; they will take quite a lot of salt.