1. In a large pot, heat the oil over moderately low heat. Add the garlic and tomatoes and cook, stirring frequently, for 5 minutes.
2. Add the cabbage, water, broth, rosemary, and salt. Bring to a boil. Reduce the heat and simmer, partially covered, until the cabbage is tender, about 20 minutes.
3. Stir in the beans and simmer until just warmed through, about 3 minutes. Ladle the soup into bowls and sprinkle the prosciutto over the top.
Wine Recommendation: There is a revolution going on in Italian wine, with more choices than ever available from the southern regions of the country. Try a Greco di Tufo, a rich, earthy, nutty white from Campania, for a perfect accompaniment to this rustic soup.
Notes: Beautiful crinkled leaves make Savoy cabbage the most attractive member of the cabbage family. It also has a unique flavor, mellower than other varieties, even a little bit sweet. But you can certainly substitute regular green cabbage here if you prefer.