Truffles, the non-chocolate kind, are edible fungi, like mushrooms. Unlike mushrooms, they grow underground near tree roots. There are two types of truffles: black truffles and white truffles. Truffles can be cooked, but are usually cleaned by hand and grated or sliced paper-thin atop warm food, which absorbs the truffle's aroma. Other cooks put truffles in closed containers with food to impart a truffle flavor. You don't need much since a little goes a long way.