Cut steak into 1/4 inch slices.

In a medium-sized bowl add steak, egg, salt, and 1 teaspoon cornstarch.

Mix and let marinate for 30 minutes to an hour.

In a small bowl whisk together 1/2 cup water, 1/4 cup sugar, ketchup, hoisin, soy sauce, oyster sauce, sweet chili sauce, crushed red pepper, and apple cider vinegar. Set aside.

When beef is done marinating add 2 Tbsp cornstarch to a medium-sized bowl, add the marinated beef (discard the excess marinade).

Add the remaining 2 Tbsp cornstarch and toss well. Shake off excess cornstarch.

Heat saucepan with oil on medium-high heat. Cook beef in batches until golden brown (about 2-3 minutes). Set aside on wire rack.

Heat a large pan on high heat and use 2 Tbsp of the oil you just fried the beef in. Add the onion and red bell pepper. Cook for 2-3 minutes, until they just start to caramelize on the edges. Add garlic and cook a few more seconds until fragrant. Set aside.

Add Beijing Sauce to the large pan and cook on high until sauce thickens(about 3-5 minutes). Add beef and vegetables into the sauce and toss to combine.

Serve Immediately!