In a bowl, season chicken thigh fillet with salt and pepper. Set aside.
In a medium bowl, combine cornstarch, all purpose flour, garlic powder, egg and water then mix well until there are no lumps.
In a shallow pan, preheat cooking oil to 375°F. Dip the chicken thigh fillet first into the prepared batter then fry in hot oil for about five minutes. Fry the chicken in batches. Drain excess oil from chicken then set aside.
In the same pan, increase the temperature of the cooking oil to 400°F. Re-fry the fried chicken pieces to have a very crispy texture for another 3 minutes or until it turns golden brown. When done remove from the pan and transfer to a plate lined with paper towels to absorb excess oil.
In a large pan over medium low heat, combine the ketchup, gochujang, honey, soy sauce, white vinegar, sugar, garlic cloves, salt, and pepper. Mix well then let it boil. Turn off the heat.
Carefully drop the fried chicken into the sauce pan with sauce. Mix well until all the chicken pieces are evenly coated.
Transfer to a plate then garnish with sesame seeds before serving.
