Heat the oil in a large pan. Add the onion, celery, carrot, garlic and pancetta and fry (sauté) over a gentle heat for 10 minutes, stirring until very soft but not brown.
Add the remaining ingredients
except the cheese. Bring to the boil, part-cover and
simmer gently for 10 minutes.
Taste
and re-season if necessary. Ladle into bowls and
sprinkle with the Parmesan before serving.