Preheat oven to 160°C (140°C fan-forced). Dry lamb and season with salt. Heat a large heavy ovenproof pot over medium-high heat, and add oil. When oil is hot, add lamb and cook, turning as needed, for 8-10 mins or until brown all over. Transfer to a plate. Pour off all but 1 tsp of fat from pot. Reduce heat to medium. Add onion and sauté for 5 mins or until golden. Stir in garlic and cook for 1 min. Stir in stock and vinegar and bring to a simmer. Add lamb, cover pot with lid slightly ajar and transfer to oven. Cook for 1½ hours.
Remove pot from oven and turn lamb over. Return to oven with lid slightly ajar and cook for 45 mins. Remove from oven. Skim fat from liquid and add the potatoes, submerging them as much as possible. Cover completely with lid, return to oven and cook for 30 mins. Add cabbage, submerging as much as possible (don’t worry if a lot of cabbage sits on top of lamb). Cover, return to oven and cook for 20 mins or until lamb, potato and cabbage are tender. Set aside for 10 mins to rest.
Meanwhile, to make dukkah, in a small frying pan over medium-high heat, toss sesame seeds, caraway, coriander, mustard and fennel seeds for 3 mins or until aromatic. Transfer to a small food processor or spice grinder with almonds, ½ tsp of sea salt flakes and ½ tsp of freshly ground black pepper. Pulse to coarsely break up spices.
Divide lamb shanks and vegetables among shallow bowls. Ladle braising liquid over, sprinkle with dukkah and parsley and serve.