Truffle Butter Foam

One of the great things about this foam is that you don’t need to cut into your truffle to get at its flavor. The aroma of a nice stinky truffle is infused directly into butter by storing it overnight with the truffle, sealed in an airtight jar. This recipe is also a template for converting any full-flavored liquid, such as juices, infusions, and full-flavored stock (or, better, consommé), into a foam. It can also be flavored rather strongly with ingredients like herbs, spices, or mushrooms