Soak the dried wood ear and shiitake mushrooms in a water around 20 minutes until fully hydrated, then julienned. (If you are in a hurry, you can soak in hot water to speed up the process)
Marinate the Pork with soy sauce, shaoxing wine, sesame oil, white pepper and tapioca starch and set aside.
Place chicken broth in a large pot and bring to a boil over medium high heat. Add spice bag, carrot, bamboo shoots, wood ear and shiitake mushrooms and tofu and simmer for 5 minutes.
Remove spice bag and stir in the marinated pork and mushroom. Once the soup is simmering again, skim off any foam that floats to the top.
Add soy sauce, dark say sauce, vinegar and bring the soup to a simmer
Mix tapioca or corn starch with water. Then slowly pour while stirring soup
When it starts simmering again, stir constantly and slowly pour egg in a thin stream
Garnished with chopped scallions and chili oil to serve