Fresh truffles are becoming available in more specialty stores, and they’re being grown with varying degrees of success in many countries, but none matches those found in France and Italy. It’s important to use enough truffles. Offering just one slice is wasteful, because you don’t get its full impact. Truffles have a short season. The best black ones come from France; I buy large quantities of them in season, poach them in mushroom stock, and freeze them for when we need them. The very best white truffles are from Alba. Only use them fresh. If you need to store them, don’t use rice, as some experts advise—it dries them out; instead, keep them in an airtight container wrapped with a moist towel. Truffles grow in clay-based soil and must be carefully scrubbed in warm water.