Soak the beans overnight in cold water. The next day, cook them in fresh water until half-tender (about 45 minutes). Drain and set aside.
In a large pan, brown the duck confit and sausage. Remove excess fat, but reserve the duck fat. Remove the sausage and confit, and in the same pan, brown the cubed pork shoulder until golden. Remove the pork.
In a pot with the reserved duck fat, sauté the onion, carrot, and garlic. Add the tomato passata and cook for another 5 minutes. Add the pork, the half-cooked beans, thyme, bay leaf, and cover with broth. Bring to a boil.
Preheat the oven to 160°C (325°F). Transfer everything to a traditional cassole or other oven-safe pot. Place the duck confit and sausage on top. Bake for 2 hours.
After 2 hours, break the crust that has formed and stir it into the beans. Bake for another hour, breaking the crust at least 2-3 more times. If desired, you can sprinkle breadcrumbs on top for an extra crispy finish.