In a large pot, bring the chicken or vegetable broth to a simmer over medium heat.
Add the sliced mushrooms, cubed tofu, and julienned bamboo shoots to the pot and cook for 5-7 minutes until the mushrooms are somewhat tender.
Stir in soy sauce, rice vinegar, chili paste, and white pepper. Adjust seasonings to taste.
Mix the cornstarch with water to form a slurry, then gradually add it to the soup, stirring continuously until the soup slightly thickens.
Remove the pot from heat and slowly pour the beaten egg into the soup while stirring gently to form egg ribbons.
Garnish with chopped green onions before serving hot.