Ribollita ('reboiled') is a Tuscan bread soup built from seasonal vegetables, such as cavolo nero or kale, cannellini beans, carrots, celery, and onion, and stale bread, which breaks down during simmering to thicken the broth to a thick, porridge-like consistency. It's traditionally made in a large batch, cooled, and reheated, or reboiled, over the following day or two, which is where the name comes from and how the flavor deepens. It grew out of using up leftover bread and vegetables, and regional versions add potatoes, zucchini, tomatoes, or cured meats like pancetta. It's usually served with a drizzle of olive oil and grated Parmesan.