Step 1

For the marinade, mix the cornflour and soy sauce, whisking with a fork until smooth. Stir in the oyster sauce, beef stock, brown sugar and sesame oil. Add black pepper to taste and whisk well. Add the beef and leave to marinate for at least 2 hours or ideally overnight.

Step 2

To make the chow mein, heat the oil in a large wok until very hot; lift the beef out of the marinade (reserving the marinade) and brown in the wok, then transfer to a plate.

Step 3

Add the garlic and ginger to the wok and stir-fry for 1 minute. Add the carrots and mangetout and stir-fry for 3 minutes.

Step 4

Add the cooked noodles and beansprouts and return the beef to the wok, then pour over the reserved marinade. Stir well to coat the noodles with the sauce. Serve immediately, with the spring onions sprinkled on top.