Heat vegetable oil in a wide ovenproof pan and fry bacon until crisp.
Brown the sausages in the same pan and set aside with the bacon.
Sauté onion, garlic, carrot, and celery for 6 minutes until softened.
Add beans, vinegar, and sugar, then simmer until liquid reduces by half.
Stir in wine, stock, bay leaves, bacon, sausages, and sliced inner cabbage leaves.
Simmer for 12 minutes until the casserole thickens.
Blend cabbage, parsley, Parmesan, pine nuts, garlic, and oil into a rough pesto.
Season the pesto and pulse bread, lemon zest, and remaining cabbage into crumbs.
Preheat the grill to a medium setting.
Drizzle pesto and breadcrumbs over the casserole and grill until golden brown.