Cut the base and top off half-a-dozen large grapefruits. Stand them upright and, turning them with a spiral motion, cut each one diagonally into four quarters so that a third of the flesh is left on the skin.
Cut each quarter into four strips of equal length. This should give you ninety-six sticks. Cover these zests with cold water and bring them slowly to the boil. Boil gently for five minutes and strain. Perform this operation four times. Once again, return the pan to the heat, this time without water but with 600 grams of caster or finely granulated sugar. Cook for about an hour over a very low flame, stirring often with a wooden spoon. Spread the zests on a grill so that excess syrup runs away.
When they are cold, roll them one by one in sugar.