Directions

1. Cut flank steak across the grain into bite-size slices about 1/4 inch thick and 2-3 inches long. Put flank steak in a large bowl. Add cornstarch, then soy sauce on top. Stir until cornstarch is dissolved and beef is coated in the marinade. Set aside for 10 minutes.
2. In a small bowl, combine sherry, hoisin sauce, sesame oil, chili oil, and ground cumin, whisking until smooth.
3. Heat a 12- to 14-inch frying pan or a wok over medium-high heat until a bead of water sizzles and evaporates on contact. Add grapeseed oil and swirl to coat the pan bottom. Spread out beef in a single layer in the pan. Let it cook undisturbed until the underside gets a nice sear, 1-2 minutes. Then cook while stirring constantly with a spatula just until beef is no longer pink (be careful it doesn’t overcook). Transfer beef to a plate and set aside.
4. Add garlic and ginger to the same pan. Stir-fry just until aromatic, 30 seconds. Add red bell pepper and stir-fry until slightly cooked but still crunchy, another 30-60 seconds. Return beef to the pan and pour in the sauce. Cook, stirring, just until the meat and peppers are well-coated with sauce, another 30 seconds.
5. Transfer beef and vegetables to a shallow bowl and sprinkle with sesame seeds and scallions.