Here's a classic Chinese version.

Put the mushrooms, tree ears and lily buds into a bowl and cover with boiling water. Let stand for 30 minutes. Meanwhile, slice the bean curd into strips and set aside.

Combine the pork shreds with the dark soy sauce in a small bowl.

Combine the light soy sauce, vinegar and salt in another bowl. Remove the black mushrooms from the soaking liquid, cut off the woody stems and discard, then slice the caps thinly and put into a bowl. Drain and rinse the tree ears and add them to the mushrooms. Remove the lily buds, cut off the woody tips, slice them in two, then pull each apart by hand into 2 or 3 shreds and add them to the mushrooms.

Heat the oil in a wok or large pot. Stir-fry the pork just until it changes color. Add the tree ear mixture and bamboo shoots; cook, stirring for 1 minute. Add the stock and bring to a boil (you may have this simmering in a separate pot), and stir in the vinegar mixture.

Adjust the seasonings.

Cook for 1 minute then add the bean curd. When boiling, give the cornstarch/water mixture a stir to recombine and stir into the soup. Cook until the soup thickens and clears slightly. Turn off the heat and slowly swirl in the beaten eggs. Transfer to a soup tureen, sprinkle with the pepper, drizzle in the sesame oil, garnish with the scallions and coriander and serve.

San Francisco Chronicle, 12/18/87.