Perfect chips

Cut the potatoes into 1 ½cm-thick chips and put into a large bowl of cold water. Gently move around with clean hands to remove some of the starch, then drain.

Cook the chips in a large pan of boiling salted water for 8-9 minutes or until the edges are just starting to soften, then drain really well. Carefully toss the chips in the colander to rough up the edges slightly. Put a cooling rack over a baking tray then lay all of the chips on top (with a little room around each) and leave to cool completely.

Fill a pan no more than ⅓ full with vegetable oil and heat to 130C or until a cube of bread browns in 1 minute. Cook the chips, in batches, for 7-8 minutes or until they are a light straw colour and have a crisp shell around them. Drain on kitchen paper and cool. The chips can be taken up to this stage in advance and kept lightly covered at room temperature.

Carefully put the chips into a large bowl and sprinkle over the potato flour. Gently toss with your hands until fully coated (be careful as the chips may be fragile).

Heat the oil to 180C or until a cube of bread browns in 30 seconds. Add the chips, in batches, and fry for 3-4 minutes or until deep golden brown. Drain on kitchen paper and sprinkle with sea salt flakes before serving.