Combine all the marinade ingredients in a bowl. Add the lamb and leave for 30 minutes.
Place noodles in a bowl, cover with boiling water from the kettle, and leave to soften for 10 minutes. Drain well, rinse under cold water then drain well again.
Heat the wok until smoking, add half the oil and stir-fry the lamb over medium heat until lightly browned on both sides. Remove the lamb from the wok, drain and set aside.
Return the wok to the heat with remaining oil and add the garlic, spring onions and black fungi. Stir-fry for a minute then deglaze with Shaoxing.
Add hoisin, soy, sugar, black vinegar and stock to the wok. Bring to the boil, stirring well. Check seasoning then return the lamb to the wok along with the noodles. Fry quickly to combine, making sure everything is well coated with the sauce, then serve.