Prepare the beef: Thinly slice the beef (if not already done) and set aside. In a small dish, combine the cornstarch with one tablespoon of water to form a smooth mixture. Set aside.

Prepare the vegetables: Slice the mushrooms, bell pepper, and prepare the snow peas. Soak the dried shiitake mushrooms in warm water for about 15 minutes, then slice them once they’ve softened.

Make the stir-fry sauce: In a separate bowl, mix the oyster sauce, light soy sauce, Hoisin sauce, and dark soy sauce. This will be your stir-fry sauce (Ingredients B). Set aside.

Cook the beef: In a wok or large frying pan, heat 1 tablespoon of vegetable oil over medium-high heat. Add the beef and sauté until it's browned and almost fully cooked, which should take about 2 to 3 minutes. Remove it from the pan and set it aside.

Stir-fry the vegetables: In the same wok, add another tablespoon of oil. Stir-fry the garlic until fragrant, then add the king oyster mushrooms, button mushrooms, and shiitake mushrooms.

Add remaining vegetables: Toss in the snow peas and bell peppers. Stir-fry for another 1-2 minutes until the vegetables are just tender but still crisp.

Combine beef and sauce: Return the beef to the wok and pour in the stir-fry sauce. Combine all the ingredients until the beef and vegetables are evenly coated. Cook for another 1-2 minutes.

Finish with flavor: Add the Shaoxing wine, sesame oil, and the cornstarch slurry. Stir for 1 minute until the sauce thickens and everything is evenly coated.

Garnish and serve: Top with thinly sliced spring onions. Serve immediately over steamed rice for a delicious, savory meal.