You'll need to begin this recipe the day before.
Preheat oven to 180C. Heat olive oil in a large casserole, add lamb and cook over high heat for 3-4 minutes, turning until browned. Add 1 cinnamon quill, allspice, cardamom, white pepper, parsley stalks, 8 onion quarters and garlic, cover with 1½ litres water and bring to a simmer. Cover and cook for 2½ hours or until meat falls from the bone. Remove meat from bone and set aside. Strain stock and reserve, discarding solids.
Combine chickpeas, cinnamon and remaining onion in a large saucepan, cover with water and simmer over medium-high heat for 20-30 minutes or until chickpeas are tender. Drain, reserve chickpeas and discard cinnamon and onion.
For yoghurt sauce, combine all ingredients and season to taste with sea salt.
Heat extra oil in a large, deep, saucepan or deep-fryer to 180C. Add Lebanese bread,
and deep-fry in batches for 30 seconds or until golden, remove and drain on an absorbent paper-lined plate.
Increase oven to 220C. Combine lamb and chickpeas in an ovenproof baking dish, add ½ cup reserved stock and cook for 10 minutes or until hot. To serve, top lamb with bread, drizzle with yoghurt sauce, scatter with parsley, sumac, nuts and ghee.