Ribollita is an Italian soup that was traditionally seen as peasant food. The great thing about this soup is that it makes an ideal base for any additional ingredients that you might want to add. Think of it as an opportunity to give a last moment of glory to any miserable veggies left at the bottom of your fridge! I keep leftover Parmesan rinds in my freezer, which I add to sauces and soups like this to give a unique rich flavour. Add a couple while the soup is simmering and simply fish them out before serving.