Place beans in a medium bowl and cover with plenty of cold water. Set aside overnight to soak.
Preheat oven to 140°C. Heat oil in a large casserole pan over high heat. Add one-third of the pork and cook, stirring, for 5 minutes or until browned. Transfer to a bowl. Repeat in 2 more batches.
Add speck to the pan and cook, stirring, for 2 minutes or until brown. Transfer to bowl. Add Chorizo and cook, turning occasionally, for 5 minutes or until brown all over. Slice thickly diagonally.
Add duck and cook for 4-5 minutes each side or until browned. Transfer to the bowl. Add onion and garlic and cook, stirring, for 5 minutes or until soft. Add pork, speck, sausage and duck, thyme and rosemary. Drain beans. Add beans, tomato and stock. Remove from heat.
Bake in preheated oven, covered, for 1 1/2 hours or until tender. Remove the duck marylands. Use forks to coarsely flake and return to the cassoulet. Combine breadcrumbs and butter in a bowl. Sprinkle breadcrumb mixture over cassoulet. Bake, uncovered, for 30-40 minutes or until top is crisp and golden. Remove from oven and serve.
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