I have to admit up top that this didn't come out as quite the restaurant style soup I was aiming at. I can think of three possible reasons why, but I really can't be sure until I buy a bowl and do some direct comparison. My first mistake was that I used Szechuan peppercorns for the 'hot' part. This is a Szechuan recipe so that is traditional, but I can't imagine any restaurants bother with it. I should have stuck with white pepper. Second, bok (or in this case mei qing) choy isn't a usual ingredient for this soup. I think it's more of a Fukien-style soup vegetable. Third, most restaurants go too light on the sour aspect. I may have overcompensated with too much vinegar. All three of these additions add to the high notes in the flavor profile so while it seems like the soup is lacking something; it may be a lack of a lack.
So, anyway, there are two philosophies on making hot and sour soup, judging from the variety of recipes. You can either stir fry everything, add the broth, thicken it up and soups on or you can boil the broth, dump in the other ingredients in turn, cook for a few minutes, thicken and serve. If I was working with a good quality chicken stock I thick I would have gone with the first version, but since all I've got is soup from a can, I went with the latter. (As soup in a can goes, Swanson low sodium chicken broth isn't too bad.) I had accumulated a good two cups of mushroom soaking liquid in the freezer from various risottos and such so I used that along with four cups of the Swanson. All chicken broth would be fine, too. I tossed in a slice of ginger, a couple cloves of garlic and a teaspoon or so of crushed Szechuan peppercorns at the start too so they could infuse their flavors.
The rest of the ingredients begin with soaking dried cloud ear fungus (a.k.a. tree ear or wood ear) and lilly buds in boiling water. While you're slicing the soaked mushrooms into strips you've got to watch out for little knotty bits on the fungus that you'll want to cut out. And you'll need to check through the lilly buds for those still on the stem. These are both mainstays of the otherwise flexible hot and sour soup recipe, but all but the best Chinese restaurants leave the lilly buds out. (I think you can pretty fairly rate a Chinese restaurant by its hot and sour soup. The main issues are that most are neither hot nor sour, but you have to look at issues like fresh vs. canned mushrooms and the presence of lilly buds once those basic requirements are met.)
Meanwhile I defrosted a quarter pound or so of pork and sliced it into strips. In retrospect I probably should have marinated it in a bit of soy sauce, rice wine and corn starch which gives it a nice soft texture in soups and stir frys but my reference recipes didn't mention it and I forgot.
Up next are bamboo shoots and water chestnuts, mei quing choy separated into stems and leaves, tofu and scallions. The water chestnuts and scallions I chopped, the rest I sliced into strips.
Once the soup was on the boil I added the cloud ear fungus, lilly buds, pork, bamboo shoots, water chestnuts and mei quing choy stems and simmered for ten minutes.
Then I added the mei quing choy leaves, tofu and fresh mushrooms and simmered for three minutes more.
Next I added the seasonings: 1 Tablespoon rice wine, 2 Tablespoons rice wine vinegar (probably too much), 1 Tablespoon dark soy sauce, 1 teaspoon salt, and red and white pepper to taste. Once that was stirred in the next addition is 2 Tablespoons corn starch in a quarter cup of water. I brought it all back to a boil to thicken, drizzled in a beaten egg and served garnished with the scallions and a few drops of sesame oil.
As I said up top, not exactly what I was hoping for but certainly not bad. It shouldn't be hard to tweak the leftovers into a better balance.