In a medium bowl, combine sliced beef, egg whites, salt, and 1 tablespoon cornstarch. Mix well, cover, and marinate for 30–60 minutes. After marinating, toss the beef with the remaining 3 tablespoons cornstarch, shaking off any excess before frying.
1 pound flank steak, 3 egg whites, ¼ teaspoon salt, 4 tablespoons cornstarch
In a small bowl, whisk together water, sugar, ketchup, hoisin sauce, soy sauce, oyster sauce, sweet chili sauce, crushed red pepper, and apple cider vinegar. Set aside.
½ cup water, ¼ cup sugar, 3 tablespoons ketchup, 6 tablespoons hoisin sauce, 1 tablespoon low-sodium soy sauce, 2 teaspoons oyster sauce, 4 teaspoons sweet chili sauce, 1 teaspoon crushed red pepper flakes, 2 tablespoons apple cider vinegar
Heat canola oil in a deep pan or saucepan over medium-high heat. Fry in batches for 2–3 minutes, until crispy and golden. Remove and drain on paper towels.
1 cup canola oil
In a large skillet or wok, heat 2 tablespoons of the frying oil over high heat. Add onion and bell pepper and cook for 2–3 minutes, until slightly caramelized.
1 red bell pepper, 1 yellow onion
Add garlic and cook for a few seconds until fragrant. Return beef to the pan, pour in the sauce, and cook on high heat for 3–5 minutes, stirring, until the sauce thickens and coats the beef.
4 cloves garlic
Garnish with green onions or cilantro and serve hot over steamed rice.
Chopped green onions