01 - Combine sliced beef with soy sauce, Shaoxing wine, cornstarch, and black pepper in a bowl. Mix thoroughly to coat all pieces. Allow to marinate for 10-15 minutes at room temperature.
02 - Whisk together soy sauce, oyster sauce, hoisin sauce, sugar, beef broth, and cornstarch in a small bowl until cornstarch is fully dissolved. Set aside for later use.
03 - Heat 1 tablespoon vegetable oil in a large wok or skillet over high heat until smoking. Add marinated beef in a single layer, working in batches if necessary. Sear for 1-2 minutes until browned but slightly pink in center. Remove beef and set aside on a plate.
04 - Add remaining 1 tablespoon oil to the hot wok. Toss in onions, bell peppers, garlic, and ginger. Stir-fry vigorously for 2-3 minutes until vegetables are crisp-tender and fragrant.
05 - Return seared beef to the wok. Pour prepared sauce over the beef and vegetables. Toss everything together continuously for 1-2 minutes until sauce thickens and coats all ingredients evenly. Adjust seasoning with additional black pepper if desired.
06 - Transfer to a serving platter immediately while hot. Serve alongside steamed white rice for a complete meal.