In a medium saucepan, combine 3/4 cup soy sauce and 3/4 cup sugar over medium heat. Stirring gently, bring the mixture to a boil, then simmer for 2-3 minutes until slightly thickened. Add 1/2 cup crushed garlic, 1/4 cup chopped green onion, 1 tablespoon sesame oil, 1 teaspoon red chili flakes, and 1/2 teaspoon white pepper. Boil for an additional minute, then remove from heat and set aside to cool.

In a large mixing bowl, place 2 pounds of cubed chicken and pour in 4-5 tablespoons of the garlic sauce you just made. Sprinkle 1 tablespoon cornstarch and 1 tablespoon vegetable oil over the chicken and mix well until the pieces are evenly coated. Cover the bowl and let the chicken marinate for at least 30 minutes, or if time allows, refrigerate overnight for enhanced flavor.

While the chicken marinates, prepare the coating by whisking together 1 1/2 cups flour, 1/2 cup cornstarch, and 1/2 teaspoon salt in a separate bowl. As you mix, add 3 tablespoons of the garlic sauce to create clumps that will adhere to the chicken.

In a large frying pan, heat about 2 inches of vegetable oil over medium-high heat until it's shimmering. While the oil heats, take marinated chicken pieces and coat them in the prepared dry mixture, pressing firmly to adhere. Carefully place the coated chicken in the hot oil in batches, frying until golden brown and crispy, approximately 3-5 minutes.

Once all chicken pieces are fried, reheat any remaining garlic sauce on the stovetop until it’s warm. Carefully toss the golden, crispy chicken in the sauce until well-coated, or serve the sauce on the side for drizzling.