In a medium saucepan, combine ¾ cup soy sauce and ¾ cup sugar, bringing the mixture to a boil over medium heat. Allow it to simmer for 2–3 minutes until slightly thickened, then add the crushed garlic, chopped green onion, sesame oil, red chili flakes, and white pepper. Cook for an additional minute, then remove from heat.

In a large bowl, add the cubed chicken, reserving about 4–5 tablespoons of the garlic sauce for later. Pour the remaining sauce over the chicken along with 1 tablespoon of cornstarch and 1 tablespoon of vegetable oil. Mix well and let marinate for at least 30 minutes.

Prepare the dry coating in a separate bowl by mixing 1½ cups of flour, ½ cup of cornstarch, and ½ teaspoon of salt. Add 3 tablespoons of reserved garlic sauce into the dry blend, mixing until you achieve a crumbly consistency.

Set a large frying pan over medium-high heat and add enough vegetable oil to cover about 2 inches of the bottom. Once shimmering, coat each marinated chicken piece in the dry mixture and fry in batches for about 5–7 minutes until golden brown and crispy.

Reheat the reserved garlic sauce in a small saucepan. Toss the fried chicken pieces in the warmed sauce or serve sauce on the side for dipping.