01 - Whisk together soy sauce, oyster sauce, hoisin sauce, cornstarch, water, sesame oil, sugar, and black pepper in a small bowl until smooth. Set aside.
02 - Heat 1 tablespoon oil in a large wok or skillet over high heat. Add sliced beef and stir-fry for 2-3 minutes until browned but not fully cooked through. Transfer beef to a plate and set aside.
03 - Add remaining 1 tablespoon oil to the wok. Add garlic and ginger, stir-frying for 30 seconds until fragrant, being careful not to burn.
04 - Add asparagus and red bell pepper to the wok. Stir-fry for 2-3 minutes until vegetables begin to soften but retain crunch.
05 - Add bok choy and continue stir-frying for 2 minutes until leaves are wilted and stems are crisp-tender.
06 - Return beef to the wok. Pour sauce over all ingredients. Stir-fry for 2-3 minutes until beef is cooked through and sauce has thickened to coat everything evenly.
07 - Taste and adjust seasoning if needed. Serve hot over steamed rice or noodles.