Prepare the sauce by combining soy sauce and sugar in a medium saucepan over medium heat until it thickens. Stir in garlic, green onion, sesame oil, red chili flakes, and white pepper, simmering for another minute.

Marinate chicken with 4-5 tablespoons of garlic sauce, cornstarch, and vegetable oil, covering and letting it rest for at least 30 minutes.

Make the dry coating by whisking flour, cornstarch, and salt in a bowl, then adding 3 tablespoons of reserved garlic sauce until well mixed.

Heat vegetable oil in a deep frying pan, then fry marinated chicken pieces coated in the dry mixture until golden brown.

Toss fried chicken in the remaining garlic sauce and serve hot.