Patate Hasselback al Burro alle Erbe (Italian Hasselback Potatoes) A hasselback potato is a whole potato sliced almost all the way through, thirty or forty times, and then roasted until the slices separate into a fan. Nothing is removed and nothing is added inside. The cut alone converts a smooth oval with very little surface into a piece of food that is almost all surface, and the oven dries and browns every exposed edge while the uncut base underneath stays soft and steamy.