I am not sure of the origin of this dish but it is a very delicious and creative way of using up leftover roast duck pieces! Especially the bits and ends. I love this and you really have to try it to know if you would too. Green mustard, roast duck pieces, dried chili peppers, some pork (if you want) make up the main ingredients of the soup. White vinegar is added for the appetisingly sour flavours in the dish.
10 cups water