Here is a recipe from Ming Tsai that I use and enjoy. It's the closest to our favorite Chinese Restaurant's hot and sour.
The amounts of vinegar and sesame can varied to adjust the taste to you liking.
TRADITIONAL SZECHUAN-STYLE HOT AND SOUR SOUP
1/2 Lb Pork, julienned
1 tsp Sesame Oil
1 tsp Soy sauce
1 tsp Cornstarch
2 Tb Peanut Oil
4 Dried Chiles, chopped
1 Tb Ginger, minced
8 C Chicken Stock
1 tsp Sugar
1 C Bamboo Shoots, julienned
1/2 C Dried Wood Ear Mushrooms
2 Eggs lightly beaten
2 Tb Cornstarch
1/4 Lb Firm Tofu, diced
TT Salt and White Pepper
5-6 Tb Rice Vinegar
2 Tb Soy Sauce
1 tsp Sesame Oil
1/4 C Scallions, chopped
2 Tb Cilantro, Minced
Combine the pork with the sesame oil, soy, and cornstarch. Marinate for 30 minutes.
Soak the bamboo shoots in water for 30 minutes, then julienne.
Re-hydrate and julienne the wood ears.
In a hot 4-quart saucepan, add the oil and sear the pork, stirring quickly then remove the pork from the pan and set it aside.
Add the chiles and ginger, and stir.
Add the stock, sugar, bamboo shoots and wood ears and bring to a boil. Season. Simmer for 20 minutes.
While the soup is boiling, drizzle in the egg to form ribbons. A slower, thin drizzle will make thinner, more delicate ribbons.
Mix the cornstarch with cold water to form a paste and add the cornstarch to the soup stirring constantly to thicken.
Add the pork and tofu.
Add the vinegar, soy, sesame oil, scallions and cilantro and check for seasoning.
Serve immediately.
Note: If you want to make the soup ahead of time, skip the last step and refrigerate the soup. Reheat the soup just before serving and add the vinegar, soy, sesame oil, scallions and cilantro and check for seasoning.