Peel the potatoes and square them off, saving the trim for something else like a soup.
Cut into even sized chips, approximately 2cm square.
Rinse in cold water, then add to a pan of cold salted water and bring to a gentle boil for 10 minutes until the chips are just fork tender.
Drain and dry on a wire rack uncovered in a fridge until completely chilled.
Heat the oil to 130°C (260°F) and drop the chips for 8 minutes, then return to the rack and dry again in a fridge or freezer.
Heat the oil to 175°C (350°F) and fry the chips for a further 4 minutes.
Sprinkle with sea salt and serve immediately.
