Slice the topside thinly across the grain. If you're having trouble getting thin slices, putting the beef in the freezer for 20–30 minutes first will firm it up.

Combine the beef with the soy sauce, Shaoxing wine, oyster sauce, cornflour, bicarbonate of soda and white pepper.

Mix thoroughly until the marinade coats the beef and starts to disappear into it.

Add the teaspoon of neutral oil and mix again.

Leave to marinate for 20–30 minutes.

Cut the spring onions into roughly 5 cm batons.

Keep the thicker white and pale-green sections separate from the softer dark-green sections. The thicker pieces can take more heat and benefit from getting a little char.

Combine the light soy sauce, black vinegar, chilli oil, sesame oil, honey and optional garlic in a large mixing bowl.

Taste it before adding the noodles.

It should taste slightly stronger, sharper and saltier than you ultimately want, because the noodles and beef will dilute the dressing.

Cook and chill the noodles

Cook the knife-cut noodles according to the packet directions until cooked but still chewy.

Before draining, reserve about ¼ cup of the cooking water.

Drain the noodles and rinse thoroughly under cold running water until completely cool. This stops the cooking and washes away excess surface starch.

Add the chilled noodles to the dressing and toss thoroughly. If the dressing isn't distributing easily, add 1 tablespoon of reserved noodle water.

Set aside while you cook the beef.

Heat a wok or large frying pan over high heat until very hot.

Add about 1 teaspoon neutral oil.

Spread the beef out rather than immediately stirring it. Let it sear briefly, then toss and continue stir-frying until browned and almost cooked through.

With a smaller pan, cook the beef in two batches rather than overcrowding it.

Remove the beef and set aside.

Char the spring onion

Return the wok to high heat.

Add another small splash of oil if the wok is dry, followed by the white and pale-green spring onion batons.

Stir-fry for about 45–60 seconds, allowing them to blister and char in places while retaining some texture.

Add the darker green sections and cook for another 20–30 seconds.

Return the beef to the wok and toss everything together just long enough to finish cooking the beef.

Give the chilled dressed noodles another toss and divide between two bowls.

Pile the hot beef and charred spring onion over the noodles, including any juices left in the wok.

You can leave it layered for serving or toss everything together immediately before eating.

Taste and finish with a little extra black vinegar or chilli oil if needed.