Peel then cut the potatoes into 7mm 1/4 inch square strips

Place cut potatoes in a saucepan with 1l water, the vinegar and 10g of salt.

Bring up to a boil, then simmer for around 8 minutes, or until the potatoes are just tender but not mushy.

Carefully place onto a wire rack over a baking sheet to steam dry.

Heat the oil in a saucepan or wok or high-sided frying pan, to 200c / 392f

Add roughly half of the dry potatoes and fry for 45 seconds to a minute.

Remove them onto the same wire rack (if you’re doing lots of fries get a second wire rack for ease)

Allow the oil to come back up to temperature before doing the next batch.

Once all are fried place the wire rack into your freezer for at least half an hour, at this stage they can stay in your freezer until you need them for 1 to 3 months.

Once ready to eat, heat your oil to 200c / 392f again, once up to temperature fry for 3 to 4 minutes until you are happy with the crispness, the longer you fry the crispier they will be!

Drain into a bowl lined with paper towel, lightly season with salt and serve.