Also called a Mexican green tomato, the tomatillo is a green fruit that is covered with a thin papery brown husk that is removed before using. It resembles a small green tomato in size and shape, once the husk is removed, and is used in Mexican and Tex-Mex dishes including guacamole, salsa and sauce. Tomatillos are mild in flavor and offer a hint of lemon and apple which is enhanced by cooking.