Cut the steak in really thin slices across the grain. Combine with soy sauce, oil, sambal oelek, and cornstarch. Set aside.

In the meantime, mince the garlic and grate the ginger. Thinly chop the white part of scallions and slice the green part into 2-inch/5 cm pieces.

Prepare the sauce by combining the ingredients in a small bowl.

Heat 1 tablespoon oil in a wok over high heat until smoking-hot and oil is shimmering. Add the beef, spread in a single layer, sear undisturbed for 30 seconds. Turn, and stir-fry for 30 seconds more, until the beef is slightly browned but not cooked through. Transfer the beef to a clean bowl.

Add 1 tablespoon oil, then garlic, ginger and white scallion parts. Cook for 30 seconds. Stir in green scallion parts, then return beef to the wok and stir-fry for 30 seconds.

Add the prepared sauce, stir-fry for 1 minute. Turn off the heat, and serve!