Cook the rice. Rinse the rice until the water runs clear. Cook according to package directions. Fluff and keep warm. For brown rice, start it earlier since it takes longer.

Slice the beef. Freeze the steak for 15–20 minutes to firm it slightly. Slice very thinly against the grain. Pat dry with paper towels and season lightly with salt and pepper.

Prep vegetables and aromatics. Cut broccoli into small florets, slice the bell pepper and onion, thinly slice the carrot, and chop the green onions. Mince the garlic and grate the ginger.

Make the sauce. In a bowl, whisk soy sauce, oyster sauce, rice vinegar, brown sugar, sesame oil, chili (optional), and broth. Stir in cornstarch until smooth. Taste and adjust for saltiness and sweetness.

Heat the pan. Preheat a large skillet or wok over medium-high until hot. Add 1 tablespoon oil and swirl to coat.

Sear the beef. Add half the beef in a single layer. Cook 1–2 minutes per side until browned but not overcooked. Remove to a plate. Repeat with remaining beef, adding more oil if needed.

Stir-fry the vegetables. Add another splash of oil. Stir-fry onion and carrot for 1–2 minutes. Add bell pepper and broccoli and cook 2–3 minutes until crisp-tender.

Add aromatics. Push veggies to the sides. Add garlic and ginger to the center. Stir 30 seconds until fragrant.

Combine and sauce. Return beef and any juices to the pan. Stir the sauce and pour it in. Toss everything to coat. Cook 1–2 minutes until the sauce thickens and glossy. If too thick, add a splash of water; if too thin, simmer another minute.

Finish and serve. Turn off heat. Stir in green onions. Spoon over warm rice. Top with sesame seeds or a drizzle of chili oil if you like.