Place the beans in a large saucepan and cover with cold water. Bring to the boil, then reduce the heat to medium and simmer for 45 minutes to 1 hour or until just tender. Drain and set aside.
Meanwhile, preheat the oven to 180oC (350oF). Heat the olive oil in a large saucepan over medium heat. Add the onion, carrot, celery and prosciutto and cook, stirring, for 5 minutes or until softened. Add the garlic and fennel seeds and cook, stirring, for 30 seconds or until fragrant.
Add the stock, water, diced tomato, cooked beans and kale. Bring to the boil, then reduce the heat to low and simmer for 15 minutes. Season to taste with sea salt and freshly ground black pepper.
Meanwhile, to make the parmesan croutons, place the bread on a large baking tray lined with baking paper. Drizzle with the olive oil, then sprinkle with the parmesan. Bake for 10-15 minutes or until golden and crisp.
Serve the soup scattered with the croutons.