Suān Là Tāng
"The perfect balance of tang and heat. Better than any takeout."
Bring stock to a boil. Add pork, cook 2 minutes. Skim any foam.
Add mushrooms, bamboo shoots, and tofu. Simmer 5 minutes.
Add soy sauce, vinegar, and white pepper. Taste and adjust — it should be noticeably sour with lingering heat.
Add vinegar in stages. You can always add more, can't take it away.
Stir cornstarch slurry, add to soup while stirring. Bring back to simmer until thickened.
Turn off heat. Slowly drizzle in beaten egg while stirring gently — this creates ribbons.
Finish with sesame oil and scallions. Serve immediately with extra vinegar and chili oil on the side.
Replace pork with shrimp and crab meat. Add at the very end to avoid overcooking.
Skip pork, use vegetable broth. Add extra mushrooms for umami.
Add fresh sliced chilies or more white pepper. Or drizzle with la-yu at the table.