Heat the oil in a large saucepan over medium heat. Add the garlic and ginger and cook, stirring, until fragrant, about 1 minute.
Add the chicken broth, vinegar, soy sauce, white pepper, sugar, and red pepper flakes. Bring to a boil and then reduce the heat to a simmer.
Add the mushrooms, bamboo shoots, bell pepper, and carrots. Simmer for 10 minutes.
In a small bowl, mix together the cornstarch and cold water until smooth. Slowly add the cornstarch mixture to the soup, stirring constantly until the soup thickens, about 5 minutes.
Add the cilantro, sesame oil, and scallions. Simmer for an additional 5 minutes. Serve hot.
Interesting Facts
Hot and sour soup is one of the most popular dishes in Chinese cuisine.
The soup is believed to have originated in the Sichuan province of China.
The soup is traditionally served with fried dough sticks or boiled rice.
The soup can be made with a variety of ingredients, such as pork, chicken, beef, tofu, and vegetables.