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 natural 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.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.