Crispy beef strips stir-fried with onion and red bell peppers then tossed in a sweet and tangy sauce. You're going to love this popular Panda Express copycat version of Beijing beef!
Prepare the steak by cutting it, against the grain, into ¼ inch thick strips about 2 inches long.
In a medium bowl, whisk together the egg, soy sauce, and 1 tablespoon of cornstarch. Add the sliced steak to the bowl and toss to coat completely. Allow the steak to marinade for 30 minutes at room temperature.
Add the remaining 4 tablespoons of cornstarch to a bowl. Remove the marinated beef from the marinade, and toss it in the cornstarch, coating each piece completely.
In a medium bowl, whisk together the brown sugar, vinegar, tomato paste, sweet chili sauce, soy sauce, hoisin sauce, onion powder, and garlic powder.
Heat the oil in a wok or large skillet over medium-high heat. Add the marinated and cornstarch-coated steak into the pan then fry the beef until browned, about 2-3 minutes. Remove the beef from the pan and set it aside.
Returning to the pan add the diced onion and chopped red bell pepper. Stir fry until the vegetables soften, about 5 minutes.
Add the beef back to the pan and pour the sauce mixture over the beef and vegetables. Stir fry everything together until the sauce begins to thicken, about 2-3 minutes.