Step 1: In a medium bowl, whisk together the sliced beef with 1 tablespoon of soy sauce, the ShaoXing wine, cornstarch, and 1 tablespoon of vegetable oil. Let it marinate for at least 15 minutes to velvet the beef.
Step 2: In a small jar or bowl, combine the remaining soy sauce, oyster sauce, sesame oil, and black pepper. Set aside for the final chinese beef and onion stir fry stage.
Step 3: Heat 1 tablespoon of oil in a wok or large skillet over high heat until smoking. Add the beef in a single layer and sear for 1-2 minutes until browned. Remove beef and set aside.
Step 4: Wipe the pan if necessary, add the remaining tablespoon of oil, and toss in the onions. Stir-fry for 3 minutes until the edges are charred but the onions are still crisp.
Step 5: Add the minced garlic and grated ginger to the onions and cook for 30 seconds until fragrant.
Step 6: Return the beef and any accumulated juices to the pan. Pour the prepared sauce over the mixture.
Step 7: Toss everything together for 1-2 minutes until the sauce has thickened and coated the chinese beef and onion stir fry components. Serve immediately.