Place the bacon and onions in a large saucepan and dry fry until the onion is softened and the bacon is browned, about 5 minutes. Start over a low heat until the fat from the bacon begins to run then increase the heat slightly.
Add the garlic and carrots. Cook for another minute or so.
Add the tomatoes and stock, and bring gently to the boil. Season well. Reduce the heat and simmer for 10 minutes.
Add the beans and courgettes and simmer for 10 minutes or until the vegetable are just tender.
Serve with a sprinkling of chopped parsley and grated cheese if desired.