Peel the potatoes and slice them into half-inch thick batons.

Place the cut potatoes in a large bowl of cold water and let them soak for at least two hours to remove excess starch.

Drain the potatoes thoroughly and pat them completely dry with clean kitchen towels.

Heat about three inches of vegetable oil in a deep pot or fryer until it reaches 350°F.

Fry the potatoes in small batches until they are golden brown and cooked through, which usually takes about 5 to 7 minutes.

Remove the chips with a slotted spoon and drain them briefly on paper towels.

Season the hot chips generously with sea salt and a splash of malt vinegar.

Split the rolls open, spread with butter or your preferred sauce, and pile the hot chips inside to serve immediately.