Soup – Thick noodle soup minus cornstarch/cornflour

One of the first things I learned in Indian cooking is that the combination of tomatoes, onions and ginger is self-thickening. As time went by, I realised that the thickening effect is far more noticable with old varieties of tomatoes - "beef" tomatoes and a lot of the modern varieties are difficult to thicken unless partially fried first.

Despite the absence of ginger, I suspect that the thickening is purely a natural action between the tomatoes and the onion, and that the tomatoes used were some particularly nice old variety.

For heat, I recommend chili oil as opposed to a paste. That and white pepper should give you a pretty solid heat component. Even though the thought initially made me go EEEEEEW, ATK does recommend a a 50/50 combination of Balsamic and red wine vinegars as a replacement for the ideal Black Chinese Vinegar, which is probably what great Chinese restaurants use. Do you eat eggs? If so, I'd certainly use one. Here's the technique, again from ATK " Without stirring soup, use soupspoon to slowly drizzle very thin streams of egg mixture (1/2 tsp corntarch, 1 tsp water beaten with 1 egg) into pot in circular motion. Let soup sit 1 minute, then return saucepan to medium-high heat. Bring soup to gentle boil, then immediately remove from heat. Gently stir soup once to evenly distribute egg."

You probably should considerably up your soy sauce. Consider too your mushrooms. "Assorted" can mean just about anything. Some mushrooms are very strongly flavored in a way that just plain clashes with Chinese Hot and Sour. That could very well account for the barnyard odor you describe. I'd recommend sticking to shiitake/oyster/woodear if you can.