Put the mushrooms in a small bowl and cover with boiling water. Allow to sit for 15 minutes, or until rehydrated and softened. Line a sieve with muslin or paper towels and place it over a bowl, then pour the mushrooms and their soaking liquid into it. Measure the strained liquid and make it up to 100 ml with water if necessary, then set aside. Remove and discard any tough stalks from the mushrooms, slice the caps and set them aside.
While the mushrooms are soaking, put the noodles in a large bowl and pour in enough boiling water to cover them generously. Soak for 4 minutes, or according to the packet instructions, until tender. Drain well and set aside.
Heat a wok or large frying pan over a high heat. Add 1 tablespoon (15ml) of the vegetable oil and, when it is hot, stir in the garlic, ginger, chilli and five-spice powder. Stir-fry for 30 seconds, taking care not to let the flavourings burn.
Add the strips of pork and continue stir-frying for about 2 minutes, or until they are cooked through. Use a slotted spoon to remove the pork from the wok and set it aside.
Add the remaining oil to the wok and heat until it is almost smoking. Toss in the capsicums, broccoli, celery and chopped mushroom caps and stir-fry for 2 minutes. Pour in the mushroom soaking liquid, soya sauce and sake, mirin or sherry, stir well, then return the pork to the wok. Continue cooking, stirring constantly, for about 1 minute, or until the pork is heated through.
Stir the noodles, then the bean sprouts into the wok and toss together briefly, just long enough to heat the ingredients without softening the bean sprouts, as they should retain their crunch.
Toss through the chopped coriander and sprinkle with the sesame oil. Serve the chow mein immediately, garnished with fresh coriander leaves.