Put the onion in a stockpot with the oil and saute over medium heat until pale gold. Add the carrot, celery, and pork and saute for about 10 minutes, stirring the vegetables and turning the pork from time to time. Add the chopped tomatoes and their juice, turn the heat down to medium-low, and cook for 10 minutes.

If you are using fresh cranberry beans, shell the beans, rinse them in cold water, and add to the pot. Stir 2-3 times, then add the broth mixed with water. Cover the pot, adjust the heat so that the liquid is bubbling at a very moderate boil, but a bit more than a simmer, and cook for 45-60 minutes or until the beans are tender. (If you are using precooked beans, cook the tomatoes for 20 minutes instead of 10 in step 3, then add the drained beans. Let the beans cook in the tomatoes for 5 minutes, stirring thoroughly, then add the broth and bring to a moderate boil.) Scoop up about 1/2 cup of beans and mash them through a food mill back into the pot. Add salt and pepper lightly.

Check the soup for density; add more water if needed, and bring the liquid to a steady boil. Add the pasta. If you are using dried pasta or macaroni, taste for doneness and stop the cooking when the pasta is very firm to the bite. (The soup should rest for about 10 minutes before serving, so it you do not stop the cooking when the pasta is very firm it will be quite mushy by the time it gets to the table.) Just before serving, swirl in the grated cheese.

NOTE: Cranberry beans are pink and white marbled beans, and they add a wonderful flavor to this soup. If they are not available use 1 cup dried great northern beans, cook as directed or 1 (21 ounce) can white kidney beans or other white beans, drained.

The soup can be prepared entirely ahead of time up to, but not including the last paragraph. Add the pasta only when you are going to serve the soup.