How to Make It
In a shallow bowl, toss the sirloin with the cornstarch and let stand for 10 minutes. Meanwhile, in a small bowl, whisk the soy sauce with the Shaoxing wine, oyster sauce, Sriracha and sesame oil.
In a wok or large skillet, heat the peanut oil until shimmering. Add the sirloin and stir-fry over high heat until browned and the edges are crisp, about 4 minutes. Using a slotted spoon, transfer the meat to a plate.
Add the ginger and garlic to the wok and stir-fry over high heat until golden, about 1 minute. Add the sirloin and scallions and stir-fry over high heat until the scallions just start to soften, about 3 minutes. Add the soy sauce mixture and stir-fry over high heat until the sauce has thickened, about 3 minutes. Season with salt and pepper. Spoon the Mongolian beef over steamed rice, sprinkle with sesame seeds and serve.