Thinly slice the beef against the grain to ensure tenderness.
In a bowl, combine the sliced beef with 1 tablespoon soy sauce , 1 tablespoon cornstarch , and a pinch of pepper. Mix well to coat the beef evenly. Let it marinate for 10–15 minutes while you prepare the other ingredients.
Step 2: Cook the Beef
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.
Add the marinated beef in a single layer and sear for 1–2 minutes per side, just until browned but not fully cooked through. Remove the beef from the pan and set aside.
Step 3: Cook the Onions and Garlic
In the same skillet, add the remaining 1 tablespoon of vegetable oil .
Add the sliced onions and cook for 3–4 minutes, stirring occasionally, until they begin to soften and caramelize slightly.
Stir in the minced garlic and cook for an additional 30 seconds, until fragrant.
Step 4: Combine and Finish the Dish
Return the cooked beef to the skillet with the onions and garlic.
Add the remaining 1 tablespoon soy sauce and oyster sauce (if using). Stir everything together and cook for 1–2 minutes, until the beef is fully cooked and the flavors are well combined.
Taste and adjust seasoning with salt and pepper if needed.
Step 5: Serve and Garnish
Transfer the stir fry to a serving plate or bowl.
Garnish with sliced green onions for a pop of color and freshness, if desired.
Serve hot with steamed rice, fried rice, or noodles for a complete meal.
