This is a traditional version of the Italian classic. The soup can be thickened with either white beans or perhaps spaghetti, and a generous spoonful of Parmesan added at the table.
Place the dried beans in a bowl, cover with twice their volume of cold water, then leave to soak overnight. Drain, then rinse the soaked beans under cold running water. Heat the chicken stock in a large pan, add the drained beans and bring slowly to the boil over medium heat. Cook for 45 minutes, or until the beans are tender, skimming the surface often.