Season the chicken. In a bowl, toss chicken with salt, pepper, soy sauce, rice vinegar, garlic, ginger, and egg white if using. Mix well to coat. Let sit 20–30 minutes while you prep the sauce and oil.

Make the sauce. In a small saucepan, combine gochujang, ketchup, honey, soy sauce, rice vinegar, garlic, ginger, and sesame oil. Bring to a gentle simmer over low heat for 2–3 minutes. Add a splash of water if it seems too thick. Turn off heat and set aside.

Heat the oil. Fill a heavy pot with about 2 inches of oil. Heat to 325°F (163°C) for the first fry. Keep a thermometer clipped to the side if you have one.

Prepare the coating. In a shallow bowl, mix potato starch, baking powder, and garlic powder. Dredge each piece of chicken, pressing so a thin, even layer sticks. Shake off excess.

First fry (cook-through stage). Working in batches, fry chicken at 325°F for 6–8 minutes (wings) or 7–9 minutes (thigh pieces) until pale golden. Don’t crowd the pot. Transfer to a wire rack set over a sheet pan. Let rest 10 minutes.

Raise the heat for the second fry. Increase oil temperature to 375°F (190°C). This high heat crisps the exterior fast without drying the meat.

Second fry (crisping stage). Fry the chicken again in batches for 2–3 minutes, until deep golden and audibly crisp. Drain on the rack.

Sauce carefully. Warm the sauce if needed. You have two options: Toss to coat: For saucy chicken, place pieces in a large bowl, add sauce, and toss quickly.

Brush or drizzle: For maximum crunch, brush or drizzle a thinner layer so the crust stays snappy.

Finish and serve. Sprinkle with sesame seeds and green onions. Serve immediately with pickled radish and cold beer or sparkling water.