This recipe makes delicious and thrifty use of the 1/4-inch (5 mm) thick rinds that remain after grating wedges of Parmigiano-Reggiano. They infuse this velvety soup with a rich salty bite.
If you are not accustomed to eating leeks, this is a tasty introduction. Serve with cherry tomatoes lightly sautéed with minced garlic and olive oil.
