Ribollita is proof that some soups are better the next day, for it means "reboiled". I always cook my own beans for this soup because they taste so much better than canned, plus they produce a flavorful broth. Also, be sure to use black kale if you can find it. Since this soup is Tuscan, why not serve it with a Tuscan red wine, such as Chianti, Montepulciano or Morellino di Scansano. It will be quite thick, more of a potage than a soup.