Method:

1. Soak the dried soybeans in an equal amount of water for more than 4 hours in advance.

2. Wash the pig's trotters with clean water, remove the hair, and cut them into small pieces. You can buy ready-made pig's trotters cut into pieces or use the whole pig's trotters, and then put the pig's trotters into cold water. Bring to a boil. When it changes color, remove and rinse with clean water to remove any foam, drain and set aside for later use.

3. Slice ginger and garlic, and pack dried chilies, peppercorns, cinnamon, fennel, and bay leaves in disposable materials for later use.

4. Put the wok on the fire, pour in the oil, add the rock sugar to melt the rock sugar, and boil the rock sugar until the color becomes darker.

5. Add the blanched pig's trotters and stir-fry evenly so that the sugar color evenly adheres to the surface of the pig's trotters.

6. Add boiling water (the amount of water should cover the pig's trotters by 3cm), soybeans (can be added with the water for soaking the soybeans), soy sauce, cooking wine, ginger slices, green onion segments and seasoning packets, and salt and bring to a boil .

7. Turn to low heat, cover and simmer for about 1.5 hours, until the pig's trotters are tender.

8. Add rice vinegar, open the lid and turn to high heat until the soup thickens.