Season the chicken. In a bowl, combine chicken, salt, pepper, soy sauce, rice vinegar, garlic, and ginger. Toss well. Let it sit for 10–15 minutes while you prep the coating and sauce.

Make the sauce. In a small saucepan, whisk together gochujang, ketchup, soy sauce, honey, rice vinegar, garlic, and sesame oil. Add 2 tablespoons water. Warm over low heat for 2–3 minutes until glossy. If too thick, add another splash of water. Turn off heat and set aside.

Coat the chicken. Add the egg white to the chicken and mix to coat. In a separate bowl, combine cornstarch and flour. Dredge the chicken pieces in the dry mixture, pressing so the coating adheres. Shake off excess.

Heat the oil. Pour oil into a heavy pot to a depth of about 1.5 inches. Heat to 325–340°F (165–170°C). Keep a steady medium heat—too hot and the coating burns before the chicken cooks.

First fry. Fry chicken in batches, avoiding crowding. Cook 4–5 minutes until pale golden and cooked through. Transfer to a wire rack or paper towels. Let the oil return to temperature between batches.

Second fry for crispness. Increase oil to 350–365°F (175–185°C). Fry the chicken again for 1–2 minutes until deep golden and extra crisp. Drain on a rack.

Coat in sauce. Warm the sauce again over low heat. Add the fried chicken and toss until evenly coated and shiny. Work in batches if needed so everything gets a thin, even glaze.

Finish and serve. Sprinkle with toasted sesame seeds and green onions. Serve hot with rice, fries, or pickled radish.