In a mixing bowl, combine the cornflour, salt, black pepper, garlic powder, and onion powder.
Toss the chicken pieces in the cornflour mixture until they are evenly coated.
Heat vegetable oil in a deep pan or wok over medium-high heat.
Carefully add the coated chicken pieces to the hot oil and fry until they are golden brown and crispy. This should take about 5-7 minutes. Remove the chicken from the oil and drain on a paper towel.
In another pan, heat 2 tablespoons of vegetable oil over medium heat.
Add minced garlic and ginger to the pan and stir-fry for about 30 seconds until fragrant.
Stir in the chilli sauce, tomato ketchup, soy sauce, rice vinegar, and brown sugar. Allow the sauce to simmer for a few minutes until it thickens slightly.
Mix the cornflour-water mixture into the sauce to thicken it further. Stir well until the sauce reaches your desired consistency.
Add the crispy chicken pieces to the sauce and toss them until they are coated evenly.
Serve your Crispy Chilli Chicken hot, garnished with some chopped spring onions or sesame seeds if desired.
