Prep the beef: Freeze the steak for 20–30 minutes to firm it up. Slice very thinly against the grain. In a bowl, toss beef with 1 tablespoon soy sauce and 1 tablespoon cornstarch. Set aside for 10–15 minutes.

Make the sauce: In a measuring cup, whisk 1/3 cup soy sauce, 2 tablespoons oyster sauce, 1 tablespoon rice vinegar, 1 tablespoon brown sugar or honey, 1 cup broth, 1 tablespoon cornstarch, and a pinch of red pepper flakes. Taste and adjust sweetness or salt as needed.

Par-cook the broccoli: Steam or blanch florets for 1–2 minutes until bright green and just tender. Drain well and pat dry so they stir-fry instead of steam.

Heat the pan: Set a large skillet or wok over high heat. Add 1 tablespoon neutral oil and swirl to coat until shimmering.

Sear the beef in batches: Add half the beef in a single layer. Let it sear undisturbed for 60–90 seconds, then stir-fry another minute until just browned. Transfer to a plate. Repeat with remaining beef, adding oil if needed.

Aromatics: Reduce heat to medium-high. Add a bit more oil if the pan is dry. Stir-fry garlic and ginger for 20–30 seconds until fragrant.

Broccoli time: Add broccoli to the pan and toss for 1–2 minutes to pick up flavor and slight char.

Sauce and finish: Return beef and any juices to the pan. Stir the sauce (cornstarch settles), then pour it in. Cook, tossing, for 1–2 minutes until the sauce thickens and coats everything. Drizzle with 1 teaspoon sesame oil. Sprinkle green onions and sesame seeds if using.

Taste and adjust: Add a splash of soy for salt, more vinegar for brightness, or a pinch of sugar if it tastes too salty.

Serve or portion: Spoon over rice or noodles and portion into meal prep containers. Let cool slightly before sealing.