1. Soak the black mushrooms in warm water. 
2. Cook the chicken breasts in simmering salted water for 10 minutes, or steam them. 
3. Peel and slice the ginger into thin sticks. 
4. Drain and rinse the bamboo shoots. Slice into thin sticks. 
5. Cut the tofu into slices, then into sticks; set aside in cold water. 
6. Drain the mushrooms and squeeze out the excess water. Cut into thin strips. 
7. Break the eggs into a bowl and beat them lightly. 
8. Cut the chicken into strips and dissolve the cornstarch in a little cold water. 
9. Bring the broth to a boil and mix in the cornstarch mixture. Whisk well and add in this order, continuing to whisk: the beaten eggs, sugar, soy sauce, chili paste, bamboo shoots, ginger, black mushrooms, vinegar, chicken, drained tofu and sesame oil. Heat over low heat, stirring occasionally, for 5 minutes. 
10. Serve hot in bowls, sprinkled with cilantro leaves. 

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Collaboration and photo: Suzi Wan - Essential Chinese products available in major grocery stores, including bamboo shoots, black mushrooms, chili paste and soy sauce.