01 - Combine the sliced beef with soy sauce, oyster sauce, cornstarch, sesame oil, and black pepper in a bowl. Mix well and marinate for 15 minutes.
02 - Cook noodles according to package instructions. Drain, rinse briefly with cold water, and set aside.
03 - Whisk together soy sauce, dark soy sauce, chili garlic sauce, brown sugar, and rice vinegar in a small bowl.
04 - Heat 1 tablespoon vegetable oil in a large wok or skillet over high heat. Add marinated beef in a single layer and sear for 1–2 minutes until just browned. Remove and set aside.
05 - Add remaining 1 tablespoon oil to the wok. Stir-fry garlic, ginger, and white parts of spring onion for 30 seconds until fragrant.
06 - Add bell pepper, carrot, and snow peas. Stir-fry for 2–3 minutes until just tender.
07 - Return beef to wok with noodles. Pour in prepared sauce and toss everything together over high heat for 2–3 minutes until well combined and heated through.
08 - Remove from heat. Garnish with green parts of spring onion, toasted sesame seeds, fresh coriander, and lime wedges if desired. Serve immediately.