Kale and Vegetable Soup with Farro

2 tablespoons extra-virgin olive oil 1 onion, diced 1 whole leek, trimmed, cut in half lengthwise, rinsed and sliced 2 cloves garlic, minced 8 cups chicken stock 2 large carrots (about 2 cups), cut in half lengthwise and sliced 2 ribs celery, diced 1 tablespoon chopped fresh thyme #189; cup farro (see note) 1-2 teaspoons kosher salt #189; bunch (about 3 cups lightly packed) kale, stems removed, chopped 1 can (14 ounces) diced tomatoes, with juices Freshly ground black pepper Parmigiano-Reggiano cheese, to taste In a soup pot, heat the oil and saute the onion over medium heat for 8 minutes, stirring occasionally. Add the leek and saute until softened, about 4 minutes. Add garlic and saute another 1 to 2 minutes. Add stock, carrots, celery, thyme, farro, and 1 teaspoon salt and bring to a boil. Turn heat to low and simmer soup, partially covered, for 15 minutes. Stir in chopped kale and the tomatoes. Bring to a boil again, turn to low, and simmer 15-20 minutes, until farro and kale are tender. Taste the soup and add additional salt if needed, plus a few grinds of pepper. Top each bowl with parmesan cheese for more depth of flavor. Serves six. Cook's notes: A type of wheat imported from Italy, farro offers a mildly chewy, nutty flavor, similar to barley. If you can't find farro, use #8531; cup barley and increase the cooking time in step one to 30 minutes, for a total of about 50 minutes. For a vegetarian version, add water instead of stock plus two Parmigiano-Reggiano cheese rinds. "Soup + Sides" by Catherine Walthers (2010 Lake Isle Press)