• 2 (15oz) cans of cannelli beans drained and rinsed
• 1 large onion, coarsely chopped
• 3 tablespoons olive oil
• 4 garlic cloves, finely chopped
• 6 cups chicken broth
• 1 (3- by 2-inch) piece Parmigiano-Reggiano rind
• 2 teaspoons salt
• 1/2 teaspoon black pepper
• 1 bay leaf
• 1 teaspoon finely chopped fresh rosemary
• 1 lb smoked or spicy sausage (optional), sliced crosswise 1/4 inch thick
• 8 carrots, halved lengthwise and cut crosswise into 1/2-inch pieces
• 1 lb kale (preferably lacinato), stems and center ribs discarded and leaves coarsely chopped
Cook onions in oil in an 8-quart pot over moderately low heat, stirring occasionally, until softened, 4 to 5 minutes. Add garlic and cook, stirring, 1 minute. Add beans, carrots, broth, cheese rind, salt, pepper, bay leaf, and rosemary and simmer, uncovered, until carrots are tender.
While soup is simmering, brown sausage (if using) in batches in a heavy skillet over moderate heat, turning, then transfer to paper towels to drain.
Stir in kale, sausage, and simmer, uncovered, stirring occasionally, until kale is just cooked. If too thick, add more stock. Season soup with salt and pepper.