In a mixing bowl, combine the sliced steak with vegetable oil, Shaoxing wine, light soy sauce, water, and cornstarch. Mix well and set aside to marinate for 20 to 30 minutes.
Meanwhile, make the sauce by dissolving raw sugar in warm chicken or beef stock, then stir in the light and dark soy sauces. Set aside.
Heat a little oil in a wok over medium-high heat. Sear the beef in batches for about 1 - 2 minutes on each side until browned, then transfer to a plate.
Add a little more oil if needed, then stir-fry the onion and white part of the spring onions for 30 to 60 seconds. Add the ginger and garlic and stir until fragrant. Pour in the sauce and bring to a simmer for 2 minutes, then stir in the cornstarch slurry to thicken.
Return the beef to the wok with the green spring onions. Toss for 30 - 60 seconds until the spring onions are just wilted and the sauce coats the beef.
Sprinkle with toasted sesame seeds and serve with steamed rice.
