There are brown lentils, green lentils, and red lentils. Brown lentils are more common and have a mild, earthy flavor. They're a great substitute for meat in tacos, tomato sauce, and Shepherd's pie. Green lentils have a robust, peppery flavor and take a long time to cook. They keep their firm texture so they're best for pilafs, side dishes, and salads.  Red lentils are the sweetest and most nutritious as they have a slightly higher protein content. They become soft and mushy when cooked and are best for soups, stew recipes, and curries.