Soak dried shiitake mushroom, wood ear mushroom and lily buds in plenty of warm water until they enlarge and become soft. It takes at least 1 hour (soak overnight if you plan ahead).

Slice the mushrooms into thin strips. Tear lily buds lengthways into thinner strands.

Cut pork, against its grain, into thin strips. Mix with cornstarch and water, then coat with oil. Set aside.

Slice carrot, bamboo shoots and tofu into thin strips. Lightly beat the egg.

In a wok or large pot, bring the stock (or water) to a full boil. Add the marinated pork. Quickly stir with chopsticks to separate the strands. Use a spoon to skim off the froth appearing on the surface.

Add shiitake mushroom, wood ear, lily buds, carrot, bamboo shoots. Leave to cook for 2 mins or so.

Turn down the heat and keep the soup at a gentle simmer. Mix cornstarch and water very well then slowly pour the slurry into the soup. Stir with a spoon/ladle.

Once the soup becomes thick, gently slide in the tofu. Slowly pour in the egg in a circular motion.

When the soup starts bubbling again, turn off the heat. Add black rice vinegar, soy sauce, white pepper and sesame oil (see note 2).

Give everything a gentle stir. Garnish with coriander or scallions. Serve warm.