Lemon grass is a stiff, reedlike grass with a sharp, lemony flavor. It contributes an aromatic, citruslike flavor to Southeast Asian recipes. The stalks are available fresh in Asian markets and well-stocked grocery stores. If you cannot find fresh lemon grass, substitute 1 tablespoon dried lemon grass or several long, thin strips of lemon peel for each 8-inch fresh stalk.
When a recipe calls for the heart of lemon grass, use only the bottom 4-6 inches of the stalk, peeling off the tough, outer leaves until you reach an inner purple ring. Chopping or crushing the stalk before using helps to release its aromatic oils.