Beef and Chinese Broccoli Stir-Fry

Trim any excess fat or tough membrane from the flank steak. Slice the beef against the grain into 1/4-inch-thick pieces, about 2 1/2 inches wide, holding the knife at a slight angle. If the beef is hard to slice, chill it in the freezer for 15-20 minutes until firm but not frozen.

Place the sliced beef in a bowl. Add 1 tsp cornstarch, 1 tsp oil, and 1 tsp soy sauce, then massage until the beef is evenly coated. Let it marinate for 20 minutes while you prepare the vegetables and sauce ingredients.

Heat a wok or large skillet over high heat until very hot. Add 1 tbsp oil, then add the beef in a single layer. Sear for 30-60 seconds, just until browned but not fully cooked through. Transfer the beef to a plate.

Add the remaining 2 tbsp oil to the wok. Add the ginger and stir-fry for about 15 seconds until fragrant. Add the garlic and Chinese broccoli, then stir-fry for 1 minute, tossing constantly, until the greens brighten and begin to soften.

Return the beef to the wok. Add the oyster sauce, soy sauce, salt, sugar, sesame oil, and hot chicken or beef stock. Toss everything together and bring the sauce to a lively simmer.