This hearty, flavorful vegetarian soup calls for just a few healthy ingredients and simple steps. A whole bunch of kale adds tons of fiber (here’s how to de-stem kale quickly), lentils contribute calcium and protein, and sweet potatoes lend some irresistible earthy sweetness. We’re guessing you’ll gobble up the whole dish immediately, but if you happen to have leftovers or make a double batch, the soup freezes and thaws splendidly. Transfer it to resalable plastic bags and stack them flat in the freezer to save space. Thaw in the refrigerator overnight and reheat on the stove until warmed through.