Crispy Chilli Beef (with Sweet Chilli) step by step guide

Name: Crispy Chilli Beef (with Sweet Chilli)
Prep time: 20 min
Cook time: 15 min
Total time: 35 min
Yield: 4 servings
Cuisine: Chinese
Ingredients: 1 pound flank steak (thinly sliced against the grain); 1 egg; 6 tablespoons cornflour (cornstarch); 1/2 teaspoon salt; 1/2 teaspoon white pepper; 4 tablespoons vegetable oil (for frying); 3 tablespoons sweet chilli sauce; 1 tablespoon soy sauce; 2 tablespoons rice vinegar; 2 tablespoons ketchup; 2 cloves garlic (minced); 1 teaspoon sriracha sauce (optional for extra heat); Sliced spring onions (green onions)