Heat the oil in a large saucepan or casserole pot over a low-medium heat and gently fry the onion, celery, carrot, courgette and pancetta for 10 mins. Add the garlic and oregano, and cook for 1 min. Tip in the beans, chopped tomatoes, purée, stock and bay leaf. Season to taste. Bring to the simmer and cook for 30 mins.
Add the pasta and greens, and cook for a further 10 mins. Ladle into bowls and scatter with the basil and some parmesan.
