The original recipe comes from Paula Wolfert's Mediterranean Grains and Greens cookbook. I have modified it so that it uses no oil. I have to watch my food budget, so I also use supermarket lentils instead of the imported ones, and bottled lemon juice instead of freshly squeezed. You can, of course, use Spanish pardina or Indian, Egyptian or Ethiopian lentils if you like, as well as freshly squeezed lemon juice. The Tuscan kale is very good with this dish, and you could add arugula, watercress or beet greens to the soup. This is a very light, savory and tasty soup that is much better tasting on the second day.