Start by combining the sliced flank steak with soy sauce, cornstarch, and sesame oil in a bowl. Toss everything together well and let it sit for at least 10 minutes while you prep your vegetables and cook your noodles.

Cook the chow mein noodles according to the package directions, then drain them and rinse with cold water to stop the cooking process. If you're using fresh noodles, they only need about 2 minutes. Set them aside and toss with a tiny splash of oil so they don't stick together.

In a small bowl, whisk together all of the sauce ingredients — the oyster sauce, soy sauce, dark soy sauce, sesame oil, sugar, white pepper, and chicken broth. Having this ready before you start stir-frying is really important since things move fast in a hot wok.

Heat a large wok or skillet over the highest heat your stove can manage. Add one tablespoon of vegetable oil and once it's shimmering hot, add the marinated beef in a single layer. Let it sear without touching it for about 60 seconds, then stir-fry for another minute until just cooked through. Remove the beef and set it aside on a plate.

Add the remaining tablespoon of oil to the same wok, then toss in the garlic and ginger. Stir quickly for about 30 seconds until fragrant, then add the onion and carrot. Stir-fry for 2 minutes until they start to soften but still have a little bite to them.

Add the shredded cabbage and bean sprouts to the wok and toss everything together for another minute. You want the vegetables to stay crisp and not turn mushy, so keep that heat high and keep things moving.

Add the cooked noodles to the wok along with the sauce. Using tongs, toss everything together until the noodles are evenly coated and heated through, about 1 to 2 minutes. Return the beef to the wok along with the green onions and give everything one final toss.

Taste and adjust seasoning as needed — a little extra soy sauce, a pinch more sugar, or a drizzle of sesame oil can go a long way. Serve immediately straight from the wok for the best texture and flavor.