Brown, green (including the prized French Puy variety), and black (often labeled ‘beluga’ because of their resemblance to caviar) lentils all cook up fairly quickly, making them perfect for adding to soups and salads. Like many beans and grains, lentils can be also cooked in large batches and then refrigerated or frozen. Yellow, white, and red lentils are almost always sold hulled, and because they don’t have skins, their cooking time is shorter.