Panda Express Mongolian beef is a regular dish in most Chinese restaurants in the US and is typically prepared using flank steak. The recipe is simple and easy to prepare, but the taste is unique.
Slice the flank steak into thin slices of 1/4 inches against the grain. Add the beef, egg, salt, and cornstarch to a medium-sized bowl and marinate for 30 minutes to an hour.
In a small bowl, whisk together the 1/2 cups water, 1/4 cups sugar, the ketchup, hoisin, sweet chili sauce, soy sauce, oyster sauce, crushed red peppers, and apple cider vinegar.
Add 2 tablespoons of cornstarch to a bowl with the marinated beef after the beef has finished marinating.
Heat the oil in a small saucepan over medium heat. Shake off the excess cornstarch from the beef with the last two tablespoons of cornstarch.
Fry the slices until they are golden brown, in batches. Use two tablespoons of the oil from frying the beef in a large pan on high heat.
Cook the onion and bell pepper for 2-3 minutes, until the edges start to caramelize. Once the garlic is fragrant, add it in and cook for a few more seconds.
Take out the veggies and place them on a plate with the beef. Stir in the Beijing Beef sauce to the large pan and cook on high until it thickens about 3-5 minutes.
Toss the beef and vegetables together with the sauce. Serve right away.