A truffle is a rare, knobby fungus that grows underground near the roots of certain trees, especially oaks and hazelnuts. Truffles look like lumpy, dirt-covered potatoes, but they have an intense, earthy aroma that chefs prize highly. Because truffles hide beneath the soil and are nearly impossible to spot, hunters traditionally use trained dogs or pigs to sniff them out in the forests of France, Italy, and other regions.

The most famous varieties are black truffles and white truffles, which can cost hundreds or even thousands of dollars per pound. Chefs shave thin slices over pasta, eggs, or risotto, where a little goes a long way. The scarcity of truffles, combined with the difficulty of finding them and their powerful flavor, makes them one of the world's most expensive foods.

The word truffle also refers to a rich chocolate candy, usually made by rolling ganache (a mixture of chocolate and cream) into balls and coating them with cocoa powder. These chocolate truffles got their name because they resemble the lumpy shape of the fungus. When someone mentions truffles at a party or bakery, they’re usually talking about the chocolate kind.