1. Chop the trotters into small pieces and soak them in water for more than 1 hour.
2. Boil the pig's feet in a pot under cold water.
3. Bring the old braised soup to a boil.
4. Put down the blanched pig's trotters. Turn to low heat and simmer for 1 hour.
5. Use chopsticks to easily pierce it through and then fish out for use.
6. Put oil in the wok, add sugar, and stir-fry on low heat until the sugar is brown-red.
7. Add boiling water [Be sure to add boiling water. So as not to burn]
8. Add green onion, ginger, star anise, cinnamon, soy sauce, salt and bring to a boil.
9. Add the soybeans soaked in advance.
10. Add the marinated pig's knuckles, turn the heat to a low heat and simmer for about 1 hour until the soup is thick.
Tips:Nagging; boil the broth of braised trotters when used up, put it in the refrigerator and freeze for next time. If there is no old soup, you can omit it. Be sure to add boiling water when frying sugar to avoid scalding.
