In a pot, bring broth to a boil. If using dried shiitake mushrooms, soak them in warm water for 10 mins, then slice.
Add mushrooms, bamboo shoots, and tofu to the broth. Simmer for 5 minutes.
Stir in rice vinegar, soy sauce, chili paste, and white pepper. Adjust to taste.
Slowly pour in cornstarch slurry while stirring. Simmer until slightly thickened (~2 mins).
Gently drizzle beaten egg in a circular motion. Let it set for 30 seconds, then stir lightly.
Turn off heat. Add sesame oil and green onions. Taste and adjust salt if needed.
Serve hot, garnished with extra green onions or cilantro.