Soak beans in water overnight. (Or, in saucepan, cover beans with water; bring to boil. Boil for 5 minutes. Remove from heat; cover and soak for 1 hour.) Drain.

Place beans in saucepan; add enough water to cover beans by 4 inches/10 cm. Bring to boil; reduce heat and simmer until tender, 1 to 2 hours. Drain, reserving enough of the cooking liquid, and adding water if necessary, to make 8 cups/2 L.

In large soup pot or Dutch oven, heat oil over medium-low heat; fry pancetta until golden and fat is rendered. Add leeks and onion; fry until soft, 8 to 10 minutes.

Increase heat to medium; add parsley, sage, bay leaf and pepper. Fry, stirring, for 2 minutes. Add carrots and celery; cook, stirring often, until celery is soft, about 5 minutes. Stir in reserved cooking liquid, tomatoes and their juice, cabbage, potatoes, Parmesan rind (if using) and salt. Bring to boil. Reduce heat and simmer, covered, until cabbage is soft, about 30 minutes.

Add kale; simmer for 10 minutes. Add beans and pasta; simmer until pasta is tender, 10 to 15 minutes. Remove bay leaf and Parmesan cheese rind (if used). Serve with Parmesan cheese on the side.

Makes 6 to 8 servings.