Marinate the lamb shank for at least 1 hour. Blanch, drain well, then set aside.
In a large pot, pan fry the lamb shank in medium high heat until golden. Add onion and shallot, fry until fragrant. Add in carrot, bay leaf, tomato, black vinegar and red wine. Pour hot water until the lamb shank is covered.
Cook the lamb shank in medium low heat until tender. About 1 hour later, season with sugar and salt.
Marinate lamb with oyster sauce for a richer flavor.