In a bowl, combine the flank steak slices with 2 tablespoons of Shaoxing wine and cornstarch. This helps tenderize the meat and infuse it with flavor. Let it sit for at least 15 minutes. It’s a game-changer that separates tender meat from tough strips.

In a separate bowl, whisk together oyster sauce, soy sauce, brown sugar, 2 tablespoons of water, and the remaining tablespoon of Shaoxing wine. Set this aside.

Heat a large pan or wok over medium-high heat. Add one tablespoon of the neutral cooking oil. Once it’s hot, add the marinated beef in a single layer. Let it sear for about 1-2 minutes without stirring, allowing that delicious brown crust to form. Flip the beef, cooking it until it’s just done before removing it from the pan.

Next, add the remaining tablespoon of oil back to the hot pan. Toss in the minced garlic and grated ginger, cooking for a minute until fragrant. Add the broccoli florets and stir-fry for about 2-3 minutes. Keep it vibrant and crisp.

Return the beef to the pan with the broccoli. Pour in the prepared sauce and add the rice vinegar and chili flakes. Stir well to combine everything and heat until bubbling. This part is crucial, as you want the sauce to coat every piece of broccoli and beef beautifully.

Once bubbling, remove it from heat. Serve hot, garnished with sesame seeds if using. This dish is now ready to impress!