Heat the oil in a heavy large pot over medium heat. Add the onion, carrots, celery,
pancetta, and garlic. Saute until the onion is translucent, about 10 minutes. Add the Swiss
chard and potato; saute for 2 minutes. Add the tomatoes and rosemary sprigs. Simmer
until the chard is wilted and the tomatoes break down, about 10 minutes.
Meanwhile, blend 3/4 cup of the beans with 1/4 cup of the broth in a processor until
almost smooth. Add the pureed bean mixture, remaining broth, and Parmesan cheese
rind to the vegetable mixture. Simmer until the potato pieces are tender, stirring
occasionally, about 15 minutes. Stir in the whole beans and parsley. Simmer until the
beans are heated through and the soup is thick, about 2 minutes. Season with salt and
pepper, to taste. Discard the rosemary sprigs (the leaves will have fallen off of the stem).
Ladle the soup into bowls and serve.