Slice the steak thinly against the grain and season with salt and pepper.

Toss the steak in cornstarch until evenly coated.

Heat 2 tablespoons of vegetable oil in a wok over medium-high heat until shimmering.

Fry the beef in batches until crispy and golden brown, about 2 minutes per side, then remove and drain on paper towels.

Bring a pot of water to a boil and cook the egg noodles according to package instructions, then drain and toss with sesame oil.

Heat the remaining vegetable oil in the wok and stir-fry the garlic and ginger for 30 seconds until fragrant.

Add the broccoli florets and stir-fry for 2–3 minutes until bright green and tender-crisp.

Stir in the soy sauce, oyster sauce, hoisin sauce, rice vinegar, sugar, and beef stock, bringing to a simmer.

Return the crispy beef to the wok along with the cooked noodles, tossing to combine and heat through.

Adjust seasoning if needed and serve immediately.