Ingredients

8 oz (230g) flank steak , or sirloin or beef flap, cut against the grain into 1/4 inch (5mm) slices
2 tablespoons oil
2 cloves garlic, minced
1/2 medium-sized yellow onion, sliced
1/2 medium-sized red bell pepper, cut into pieces
cornstarch, to dust beef for deep-frying
salt and sugar , to taste

Mariade:
1 egg, beaten
1/2 teaspoon cornstarch
1 dash ground white pepper
1/2 teaspoon salt

Beijing Sauce:
4 tablespoons water
2 tablespoons sugar
1 1/2 tablespoons ketchup
3 tablespoons hoisin sauce
2 teaspoons light soy sauce
1 teaspoon oyster sauce
2 teaspoons sweet chili sauce
1-2 teaspoons crushed chili peppers
1 tablespoon apple cider vinegar

Directions

Prepare the Marinade in a bowl and mix well. Marinate the beef for 15 minutes.

In a separate bowl, mix all the Beijing Sauce ingredients and set aside.

Place the cornstarch in a bag or bowl. Toss the marinated beef in the cornstarch, coat it well, and set aside in the refrigerator.

Heat enough oil over high heat. Coat the beef slices with cornstarch again, making sure they are well coated. Shake off the excess cornstarch. Deep fry the beef slices in small batches for 1-2 minutes, or until they are light golden brown. Remove and drain on paper towels, then set aside.

In a wok, heat oil over high heat. Stir fry the onion and bell pepper until fragrant and slightly charred, then add the garlic and stir fry for 10 seconds. Remove them from the wok.

Heat the wok again over medium-high heat, add the Beijing Sauce, and let it simmer until thickened. Adjust seasoning to taste. Add the deep fried beef, onion, bell pepper, and garlic back into the wok.

Stir for 1 minute until the beef is cooked and coated with the sauce.