Prep the beef: Freeze the steak for 15 minutes to firm it up. Slice thinly against the grain, about 1/8 inch thick. This keeps the beef tender and quick to cook.

Make the sauce: In a bowl, whisk soy sauce, oyster sauce, hoisin (if using), brown sugar, rice vinegar, black pepper, and beef broth. Stir in 1 tablespoon cornstarch until smooth. Set aside.

Marinate briefly: Toss half of the sauce with the sliced beef and let it sit for 10–15 minutes while you prep the vegetables. Reserve the remaining sauce for cooking.

Prep the broccoli: Cut into even, bite-size florets. Peel and slice the thick stem if you like—it’s great in stir fries. Mince the garlic and ginger.

Blanch the broccoli (optional but recommended): Bring a small pot of salted water to a boil. Cook broccoli for 45–60 seconds, just until bright green and slightly tender. Drain and rinse under cold water. This step keeps it crisp-tender later.

Heat the pan: Use a wok or large skillet. Add 1 tablespoon oil and heat over high until shimmering. You want the pan hot to sear the beef quickly.

Sear the beef in batches: Add a single layer of beef and cook 1–2 minutes per side until browned but not fully cooked through. Transfer to a plate and repeat with more oil if needed. Avoid crowding the pan to prevent steaming.

Aromatics time: Reduce heat to medium-high. Add a splash of oil if the pan looks dry. Add garlic and ginger, stirring for 20–30 seconds until fragrant. Don’t let them burn.

Broccoli in: Add the blanched broccoli and toss for 1–2 minutes to warm and coat with aromatics. If you skipped blanching, stir fry 3–4 minutes until crisp-tender.

Combine and sauce: Return beef and any juices to the pan. Stir the reserved sauce, then pour it in. Cook 1–2 minutes until the sauce thickens and glazes everything. If you want it thicker, mix 1 teaspoon cornstarch with 1 tablespoon water and stir it in.

Finish: Turn off the heat. Stir in sesame oil and green onions. Add chili flakes or chili garlic sauce if you want a kick. Taste and adjust with a splash more soy or a squeeze of lime.

Serve: Spoon over hot rice and sprinkle with sesame seeds. Eat right away for the best texture.