This Renaissance soup was said to be a favourite of Leonardo da Vinci (who was, apparently, vegetarian). One of the best known versions for this traditional Florentine soup was jotted down in the 1500s by court chef, Cristoforo da Messiburgo, and describes sliced onions cooked in vegetable broth and enriched with ground almonds, vinegar, sugar and cinnamon. Some like to think this was the inspiration for French onion soup, introduced by Catherine de’ Medici when her Florentine chefs moved with her to Paris.
Today’s carabaccia is a mellow, earthier version of the spiced Renaissance soup that relies on slow cooking to draw out the sweetness of the onions. It is extraordinarily humble but it shows how a delicious comforting meal can be made with relatively little. A springtime version includes fresh peas and broad beans, which freshen the soup and add some pretty colour, but I am a fan of simply adding one egg per person, poached in the soup itself.