Soak the mushrooms and lily flower stalks in hot water for 1/2 hour. Stir-fry the pork in oil, add the mushrooms, bamboo shoots, lily flower stalks, soy sauce, salt, and chicken broth. Reduce heat and simmer for 3 minutes. Add the tofu, white pepper, and vinegar, bring to a boil again.
Mix the cornstarch with water and add the egg while continuing to stir. Add the sesame oil. Garnish with scallion.