Heat oil in a heavy large pot over medium heat. Add the onion, carrots, celery, pancetta, and garlic.

Add the swiss chard and cauliflower (or turnip); saute for 2 minutes. Add the tomatoes and rosemary sprig. Simmer until the chard is wilted and the tomatoes break down, about 10 minutes.

Meanwhile, blend 3/4 cup of the beans with 1/2 cup of the broth in a blender until almost smooth. Pureed bean mixture and remaining broth, to the vegetable mixture.

Simmer until the cauliflower (or turnip) 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. Discard rosemary sprig. Season with salt and pepper, to taste.