Preparation:

Step 1: Prepare the Beef

Start by slicing the beef into thin strips, cutting against the grain for maximum tenderness. Combine the beef with cornstarch, soy sauce, Shaoxing wine, and sesame oil in a mixing bowl. Mix thoroughly to ensure every slice is well-coated, then set aside to marinate for at least 15 minutes.

Step 2: Make the Sauce

In a small bowl, mix soy sauce, oyster sauce, hoisin sauce, rice vinegar, brown sugar, chili flakes, and water. Stir until the sugar dissolves and the ingredients are fully blended. This sauce will serve as the flavorful base for the dish.

Step 3: Cook the Beef

Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. When the oil is shimmering, add the marinated beef. Sear the slices for 2-3 minutes on each side until browned and cooked through. Transfer the cooked beef to a plate and set it aside while preparing the vegetables.

Step 4: Stir-Fry the Vegetables

Add the remaining tablespoon of vegetable oil to the skillet. Toss in the minced garlic and grated ginger, sautéing for about 30 seconds until fragrant. Next, add the bell peppers and zucchini. Stir-fry the vegetables for 3-4 minutes, ensuring they remain crisp and vibrant.

Step 5: Combine and Finish

Return the beef to the skillet, then pour in the prepared sauce. Toss everything together so that the beef and vegetables are evenly coated. Finally, add the peanuts and sliced green onions, cooking for an additional 1-2 minutes to meld the flavors. Serve immediately for the best taste.