Stir-Fried Beef with Pickled Mustard Greens (Haam Choy)

In a medium bowl, combine the thinly sliced flank steak with cornstarch, baking soda, water, oyster sauce, and 1 tsp vegetable oil. Mix until the beef is evenly coated, then let it marinate for at least 30 minutes or refrigerate overnight for deeper flavor.

While the beef marinates, prepare the remaining ingredients. Rinse the pickled mustard greens well if they are heavily salted, then slice them. Slice the ginger, mince the garlic, separate the scallion whites and greens, and cut the red bell pepper into thin strips. In a small bowl, stir together the chicken stock, sugar, white pepper, light soy sauce, sesame oil, and any remaining oyster sauce for the sauce mixture.

Heat a wok or large skillet over high heat until very hot. Add oil to coat the pan, then spread the beef in a single layer. Sear for about 1 minute per side, just until browned but not fully cooked through. Transfer the beef to a plate and keep the juices.

Reduce the heat to medium and add a little more oil if the wok looks dry. Add the ginger and stir-fry for about 15 seconds, until fragrant. Add the pickled mustard greens and cook for 30 seconds, stirring, until slightly seared and less wet.