Put a kettle of water on to boil. Put the stock on to heat and preheat the oven to low.
Put the noodles into a bowl, cover with boiling water and leave to soak for 6 minutes, or cook according to the packet instructions.
Remove the duck skin and cut the flesh into 1cm x 7 1/2 cm strips. Put into a bowl with 1 tablespoon soy sauce and mix.
Peel and chop the garlic, trim and slice the spring onions; put aside. Trim and slice the mixed vegetables into matchstick-sized strips. Drain and rinse the noodles.
Heat half the oil in a large wok or frying pan. Add the duck and stir-fry for 4–5 minutes. Transfer to a dish and keep warm in the oven.
Heat the remaining oil in the wok or frying pan. Add the garlic and spring onions, mixed vegetables and corn, and stir-fry for 15 seconds in the wok, or for 30 seconds in the frying pan.
Return the duck to the pan, add the hoisin sauce and the hot stock and simmer for a few minutes.
Blend the cornflour with 1 teaspoon cold water and stir into the pan, along with the bean sprouts. Cook for 1–2 minutes, then add the noodles and the remaining soy sauce. Toss well, reheat for 3–5 minutes, then serve.
Chicken breast fillets, or a mixture of beef and chicken strips, can be used instead of the duck.