way
1. An old duck weighing about 2 kg, walnuts and ginger sliced for later use.
2. Peel the yam, cut it into large pieces with a hob, and wash it for later use.
3. A packet of old duck soup with Mao Ge.
4. Boil a pot of boiling water, and add the old duck until it is cut off.
5. Pick up the duck and pour out the boiled water.
6. Change a pot of fresh water again, and add the old duck, walnuts, ginger, and Mao Ge old duck soup.
7. Cover the high-pressure pot cover, simmer on low heat for 20 minutes after large fire.
8. Steam, open the lid, add yam, cover the lid again, and simmer on low heat after boiling 10 minute.
9. Serve in a soup bowl, and a pot of fragrant old duck soup will be ready.