01 - Combine the sliced beef with 1 tbsp soy sauce, 1 tsp cornstarch, and 1 tsp sesame oil in a bowl. Mix thoroughly and let it marinate for 10 minutes.
02 - Whisk together soy sauce, oyster sauce, hoisin sauce, rice vinegar, brown sugar, garlic, ginger, cornstarch, and water in a separate bowl. Set aside.
03 - Heat 1 tbsp vegetable oil in a large wok or skillet over high heat. Add the marinated beef in a single layer and stir-fry for 2 to 3 minutes until just browned. Remove from the wok and set aside.
04 - Add the remaining 1 tbsp oil to the wok. Stir-fry carrots for 2 minutes then add snow peas and continue stir-frying for 2 more minutes until the vegetables are crisp-tender.
05 - Return the beef to the wok. Pour in the prepared sauce and stir to combine. Cook for 1 to 2 minutes until the sauce thickens and coats the beef and vegetables evenly.
06 - Remove from heat and garnish with sliced spring onions if desired. Serve immediately over steamed rice or noodles.