Cut the peeled and quartered potatoes lengthwise into slices 1/8″ (3 mm) thick. Wash with cold water and dry them with a cloth.
Place them in a hot oil bath and fry them on high heat until they come up to the surface. The potatoes will have softened in the meantime.
Remove with a slotted spoon or wire basket to drain the oil and then immediately put them in another very hot oil bath. The slices will start to swell and a golden crust will form on their surface.
Remove them with a slotted spoon or wire basket to drain and serve immediately, sprinkled lightly with salt.