As Deborah Madison state in her cookbook containing this recipe, "Vegetable Soups from Deborah Madison's Kitchen": "As in the Provencal gratin of chickpeas and spinach, this soup unites the two with bread crumbs and an important final thread of fruity olive oil. This is one soup I make using dried chickpeas. The flavor of a long-simmered chickpea is nutty, sweet, and rich--and not at all like a canned chickpea. Plus you'll need 6 or more cups of flavorful broth, which is what you'll get if you cook your own."