Prepare the beef: In a medium bowl, toss the thinly sliced beef with a pinch of salt and pepper. Set aside.

Heat the oil: In a large wok or skillet, heat 2 tablespoons of vegetable oil over medium-high heat. Once hot, add the chopped garlic and stir-fry until fragrant, about 30 seconds.

Cook the beef: Add the sliced beef to the wok and stir-fry for 2-3 minutes until browned but still tender.

Cook the mushrooms and vegetables: In the same wok, add a little more oil if needed, then toss in the king oyster mushrooms, button mushrooms, and shiitake mushrooms. Next, add the snow peas and bell peppers, cooking for another 2 minutes.

Add the sauce: Return the beef to the pan and pour in the stir-fry sauce (oyster sauce, light soy sauce, Hoisin sauce, and dark soy sauce). Mix well, ensuring all the ingredients are coated evenly in the sauce.

Thicken with cornstarch slurry: Slowly stir in the cornstarch slurry to thicken the sauce. Stir continuously for 1 minute until the sauce reaches your desired consistency.

Finish with aromatics: Drizzle the sesame oil over the stir-fry and pour in the Shaoxing wine.

Garnish and serve: Sprinkle with chopped spring onions and serve immediately with steamed rice or noodles.