Finely chop the onion, leek carrot, and celery and fry with the oil in a large earthenware pan. Add salt, the peeled and chopped tomatoes, sage and basil and cook, adding water until it becomes smooth and creamy, neither too thick nor too runny. The soup should be served tepid, with olive oil drizzled on top. The flavour can be pepped up with a dash of chili pepper. The forerunner of this dish was called panunto or pancotto and it contained no vegetables at all.
Indeed the original recipe was without tomatoes, as it dates from long before the discovery of America and their arrival in Europe. The ingredients were therefore simply bread, oil, garlic and salt and this tasty, mushy mixture was often used to wean babies.