Hot and sour soup is a spicy, tangy soup made of fresh vegetables, bamboo shoots, tofu, egg, dried mushrooms, and chicken flavor stock, spiked with soy sauce, Zhejiang vinegar, and sesame oil.
Bring the chicken stock to a boil in a large pot. Drain the wood ear mushrooms and lily buds, trim off all the hard ends, and cut them into thin slices.
Once the 8 cups of chicken stock are boiling, add wood ear mushrooms, lily flower, sliced tofu, tomato slices, and bamboo shoots. Reduce the heat to low, cover, and simmer for 5 min.
Whisk together the white vinegar, in a separate bowl, combine the seasonings and mix well. When the base comes to a boil, add the seasonings, and simmer over high heat for 2-5 minutes.
Add the cornstarch and stir constantly until thickened. This should take about 2 minutes.
Continue to stir and pour in the eggs in a very slow stream. The eggs should form thin, almost transparent ribbons. Remove from the heat and season with the sesame oil and more vinegar or pepper to taste.
Garnish with the green onion and serve immediately.
Notes
If you are a Vegetarian, substitute vegetable stock for the chicken stock.