Toss pork with dark soy sauce in a bowl until pork is well coated.

(If using fresh mushrooms of substitutes, you may skip this step.)

Soak black and tree ear mushrooms in 3 cups boiling-hot water in another bowl (water should cover mushrooms), turning over black mushrooms occasionally, until softened, about 30 minutes. (Tree ears will expand significantly.)

Cut out and discard stems from black mushrooms, then squeeze excess liquid from caps into bowl and thinly slice caps.

Remove tree ears from bowl, reserving liquid, and trim off any hard nubs.

If large, cut tree ears into bite-size pieces.

Stir together 1/4 cup mushroom-soaking liquid (discard remainder) with cornstarch in a small bowl and set aside.

Meanwhile, soak lily buds in about 1 cup warm water until softened, about 20 minutes, then drain.

Trim off tough tips of lily buds.

Cut lily buds in half crosswise, then tear each half lengthwise into 2 or 3 shreds.

Cover bamboo shoots with cold water by 2 inches in a small saucepan, then bring just to a boil (to remove bitterness) and drain in a sieve.

While bamboo shoots are boiling, use a separate bowl to stir together vinegars, light soy sauce, sugar, and salt.

Heat a wok over high heat until a bead of water vaporizes within 1 to 2 seconds of contact.

Pour peanut oil down side of wok, then swirl oil, tilting wok to coat sides.

Add pork and stir-fry until meat just changes color, about 1 minute, then add black mushrooms, tree ears, lily buds, and bamboo shoots and stir-fry 1 minute.

Add broth and bring to a boil, then add tofu.

Return to a boil and add vinegar mixture. Stir cornstarch mixture, then add to broth and return to a boil, stirring. (Liquid will thicken.)

Reduce heat to moderate and simmer 1 minute.

Beat eggs with a fork and add a few drops of sesame oil.

Add eggs to soup in a thin stream, stirring slowly in one direction with a spoon.

Stir in white pepper, then drizzle in remaining sesame oil and divide among 6 to 8 bowls.

Sprinkle with scallions and cilantro before serving.