In a large mixing bowl, add the sliced flank steak, cornstarch, 1 tablespoon of soy sauce, and sesame oil. Toss well to coat all the beef evenly.
Allow the beef to sit for 10 minutes while you prepare the vegetables.
Separate the white and green parts of the green onions and set aside.
In a wok or large skillet, heat 1 tablespoon of vegetable oil over high heat.
Add the beef in a single layer.
Cook for 2 to 3 minutes without stirring to allow the beef to develop a deep brown sear on the bottom.
Flip the beef and cook for another 1 to 2 minutes until just cooked through.
Remove the beef from the pan and set aside.
Add the remaining 1 tablespoon of vegetable oil to the wok.
Add the minced ginger and the white parts of the green onions, the sliced white onion, and the red chili pepper.
Stir and cook for about 30 seconds until fragrant.
Return the beef to the wok.
Add the remaining 1 tablespoon of soy sauce, oyster sauce, sugar, black pepper, and water.
Toss everything together and cook for 1 to 2 minutes until the sauce thickens and coats the beef.
Add the green parts of the green onions.
Stir for 30 seconds until the onions are bright green and slightly wilted.
Remove from heat and serve immediately.
Notes
7 WW Smart Points
Tips and Tricks
Slice the beef thin. Thin slices cook faster and stay tender. Aim for slices no thicker than ¼ inch. If the beef is hard to slice, place it in the freezer for 15 to 20 minutes before cutting. It firms up just enough to make clean, thin cuts much easier.Do not skip the marinade rest time. Letting the beef sit with the cornstarch, soy sauce, and sesame oil for 10 minutes helps tenderize the meat and gives the sauce something to cling to when it hits the heat.Use high heat. A hot pan is what gives the beef that deep brown sear. If the pan is not hot enough, the beef will steam instead of sear. Let the oil heat fully before adding anything to the pan.Cook the beef in a single layer. Crowding the pan lowers the temperature and prevents browning. If needed, cook the beef in two batches rather than piling it all in at once.Have everything ready before you start. Stir fry moves fast. Chop the vegetables, measure the sauces, and have everything within reach before the heat goes on.
Storing and Reheating
Storing: Allow the stir fry to cool completely before transferring it to an airtight container. Store in the refrigerator for up to 4 days.Reheat on Stovetop - Place a serving in a skillet or saucepan over medium-low heat. Add 1 to 2 tablespoons of water to loosen the sauce. Stir until heated through.Reheat in Microwave - Place a serving in a microwave-safe dish and cover loosely. Heat in 60-second intervals, stirring between each, until warm throughout.Freezing: This recipe can be frozen for up to 2 months. Store in a freezer-safe container and thaw in the refrigerator overnight before reheating.