1) To make chicken stock, add all the ingredients to a large, heavy stockpot. Bring to a simmer, then turn heat down to low.
2) Simmer, partially covered, for about 3 hours. Strain out the solids and use the stock in the soup.
3) Add dried fungus and mushrooms to 3-4 cups boiling water. Let sit for 20 minutes. Strain mushrooms and slice thinly.
4) Drain and chop bamboo shoots and cube tofu.
5) In a large, heavy pot, add vegetable oil, ginger, garlic, and chili garlic sauce. Cook over medium heat until they ginger and garlic are very fragrant, but be careful not to burn them, about 3-4 minutes.
6) Add soy sauce and rice vinegar and stir to combine.
7) Add bamboo and mushrooms.
8) Pour in chicken stock and bring to a simmer. Simmer over low heat for 15 minutes.
9) Make a slurry with the cornstarch and water until it’s a light mixture. Slowly stir the slurry into the soup.
10) Stir in tofu and continue to simmer. Season with a pinch of sugar and ground pepper.
11) Beat egg and drizzle egg into soup mixture.
12) Serve soup garnished with cilantro and scallions.