Method

1. Heat the oil either in a heavy-based saucepan or in a deep fat fryer to about 140C/285F – if you are doing this in a pan, you will need a thermometer to check the temperature. Do not leave the pan or fryer unattended.

2. While the oil is heating, peel the potatoes and cut into chips.

3. Blanch the potatoes in the hot oil. Once cooked through, but not coloured, remove the potatoes using a slotted spoon and place on kitchen paper to drain.

4. Turn the temperature of the oil up to 170C/340F and add the chips back to the pan or deep fat fryer. Fry until golden-brown on the outside. Remove again using a slotted spoon and drain on kitchen paper.

5. Season with sea salt and black pepper. Shake well to ensure the chips are evenly coated with the seasoning.

6. Serve with the Parma ham, a good dousing of vinegar and both cheeses scattered over.