Soften the chopped celery and carrot in a little extra-virgin olive oil with one clove of garlic. Then add the chopped tomatoes, sugar and salt. Let it simmer for 40 minutes. Heat the vegetable stock and then pour in the prepared tomato sauce. Add in the stale bread, the remaining cloves of garlic, a little extra-virgin olive oil and the basil. Cook the mixture until the stock has been completely absorbed. Serve the soup in a bowl garnished with a little extra-virgin olive oil and a leaf of basil. Sprinkle with parmesan to taste.