"Hot and sour soup" is a Chinese soup said to come from the provinces of Beijing or Sichuan (both in opposite directions) but it is eaten in many versions all over the world. While the name hot would certainly make one associate it with the spicy food of Sichuan, the heat in this soup doesn't come from commonly used red chillies such as Yien Tsin or Chi Chien but from white pepper.
During my time in China I never saw this soup on a menu in any upscale Shanghai or Beijing restaurant but I did eat it at night markets and hot pot restaurants. It varied, some had thinner broths and bigger pieces of meat, some were watery but they were pretty close to the versions I've eaten in the United States and India. The ones that really stood out however were the broths that were particularly fresh and flavourful and not too glutinous and there was enough texture from bits of meat and mushrooms in the soup to make it an enjoyable eating experience.
In Mumbai Lings Pavillion does a good hot and sour but my favourite is available at the Willingdon Club- an old world gymkhana style club in Mahalaxmi. IN NYC I like Sichuan Gourmet in the Garment district and the hot and sour soup at Vanessa's Dumpling House is very good too.
Who makes your favorite?
The Chinese hot and sour soup is usually meat-based and has a thinner broth, the American version has a thicker broth that imitates the American Chinese egg drop soup- the technique of thickening a broth with whisked eggs. The sour comes from Chinese black vinegar a dark, sour Chinkiang or Zhenjiang) vinegar made by fermenting black glutinous rice. This is not available everywhere so use some red balsamic mixed with sharp white vinegar.
Most versions in China had lily buds, wood ear mushrooms, bamboo shoots and pork. Wood ear also known as black fungus and cloud ear mushrooms are available here
Dried day lily are tiger lily buds- tiger lily is a flower used ornamentally in India and comes in bright orange and yellow. If you don't have them omit them entirely. I also soak my mushrooms and day lily buds, in hot broth to extract more flavour from them.
If you use fresh mushrooms, slice finely and then sautée them in a pan to extract the liquid before you add them to the broth.
Jinhua ham a kind of smoked ham is used in the broth along with chicken bones. You can substitute with prosciutto or just a regular smoked ham. Traditionally in India the soup is made entirely with chicken. In India we add bits of carrot, even celery to the soup which I think really adds flavour and texture.
While this is a hot and sour soup, in India some amount of sweetener is added to to it to balance flavours. In Sichuan Jiuniang, also called laozao a sweetened rice wine is often used in desserts and soups. China like India uses many sugarcane products in the form of rock sugar and brown sugar.
For the Broth: (see note)
500 grams raw chicken bones and leftover such as feet roughly chopped and washed clean
150 grams Jinhua ham or proscuitto or smoked ham chopped
2-inch fresh peeled ginger root, sliced coarsely
5 cloves garlic, smashed but not pureed
6 green onions or scallions, halved
1 6 inch stick of celery coarsely chopped
2 teaspoons cornstarch
1 tablespoon light soy sauce
1 tablespoon toasted sesame oil
salt to taste
4 dried wood-ear mushrooms or use dried shiitake, finely chopped (see notes below instructions)
5 dried day lilies, finely chopped (see notes below instructions) or 2 tbsp very finely chopped celery leaves
1/2 cup very finely minced carrots
100 grams extra firm tofu, cut into small cubes
120 grams trimmed pork shoulder or loin, cut into small cubes or used raw chicken breast
1 large egg, whisked
Jiuniang or laozao (rice wine sweetener) or use brown sugar if required
1 1/2 teaspoons freshly ground white pepper or to taste
1/4 cup Chinkiang (black) Chinese vinegar or use 1 tbsp balsamic vinegar and 2 tbsp white vinegar
1/4 cup thinly sliced green onion bulbs or scallions along with an inch of green stalks
1/4 cup fresh coriander or cilantro leaves (thick stalks removed and leaves washed)
For the Broth:
Combine all the ingredients in a large stockpot. Add enough water to cover the ingredients by about one inch. Bring to a boil over high heat. Cook for 1 hour, skimming off the scum and fat with a.small sieve from time to time. Reduce until you have 1.25 litres of broth. Pour broth through a fine strainer into a large pot. Discard all the pieces of meat, spices and vegetables.
For the soup:
Remove a cup of boiling broth and soak the dried and sliced mushrooms and lily buds in it for 5 minutes. Add 2 teaspoons cornstarch and mix until dissolved. Add to broth.
Stir in soy sauce and sesame oil. Add carrots and boil broth again and season to taste with salt.
When broth is ready, add sliced wood-ears, lilies, tofu, chicken or pork. Add the celery leaves if you don't have lily buds.Cook 5-6 minutes on a medium heat until meat is cooked. Pour the egg into the broth in a thin steady stream and stir vigorously. Switch off flame. Taste soup for salt and add sweetener if required.
Assembly: Just before serving, rewarm soup if required and stir in white pepper and vinegar. Add sweetener if required. Serve with green onions, coriander leaves and extra vinegar on the side.