Slow Cooker Cassoulet

Name: Slow Cooker Cassoulet
Ingredients: 450 g dried cannellini or haricot beans, or 2 x 400 g tins of beans; 1.5 kg boneless pork shoulder, cut into 2-inch pieces (you can ask your butcher to do this for you); salt and freshly ground black pepper; olive oil; 3 medium onions, coarsely chopped; 500 ml dry white wine (or use stock or water if you prefer not to use alcohol); 60 ml tomato puree; 2 x 400 g tins whole plum tomatoes, drained and coarsely chopped; 500 ml chicken stock; 450 g fully cooked or smoked chorizo or garlic sausage links, sliced on the diagonal; 1 garlic head, halved crosswise; 100 g breadcrumbs; a handful of chopped fresh flat-leaf parsley, plus extra for garnish; crusty bread, to serve