Actually the tiny, tuberous roots of an African plant of the sedge family, chufa "nuts" are immensely popular in Spain and Mexico, primarily as a base for the refreshing drink, horchata. They have a brown, bumpy skin and a sweet, chestnutlike flavor. Dried chufas are available in bags in many Latin markets and health-food stores. Store them, tightly wrapped, in a cool, dark place for up to a year. Besides their use in horchatas, chufas make an excellent snack. They're also known as earth almonds, earthnuts and tiger nuts.