Bean soup

Method

1. Put the beans in a bowl, cover with cold water and soak overnight. The next day, drain them in a colander. Put them in a large saucepan, cover with cold water and bring to the boil over medium heat. Lower the heat and simmer for 1–1½ hours. Skim off any froth that forms on the surface with a slotted spoon.
2. Heat the butter and half the olive oil in another large saucepan over medium heat and sauté the onion, garlic, oregano, bay leaves and carrot until softened or for about 5 minutes. Add the lamb and cook, stirring, until browned. Add the tomato purée, passata, and remaining olive oil. Season generously with sea salt and freshly ground black pepper and cook for a few minutes.
3. When the beans are cooked, drain them in a colander and add them to the saucepan with the other ingredients. Add enough cold water to just cover the mixture and bring to the boil. Lower the heat, cover with a lid and simmer, stirring occasionally, for about 1 hour or until the beans are tender. Add a little more water if the soup is too thick.