Thinly slice the beef against the grain and season lightly with black pepper.
Blanch the broccoli florets in boiling water for 2 minutes, then drain.
Heat vegetable oil in a wok or large skillet over high heat.
Sear the beef for 2–3 minutes until browned, then remove and set aside.
Stir-fry the minced garlic for about 30 seconds until fragrant.
Return the beef to the pan, add the broccoli, soy sauce, and oyster sauce, then toss everything together for 2–3 minutes until well coated and heated through.
Serve immediately with steamed rice or noodles.