Dry the chicken. Pat the chicken pieces very dry with paper towels. Dry skin is what lets the coating turn crisp.

Mix the coating. In a large bowl, whisk the potato starch, flour, baking powder, salt and white pepper.

Coat the chicken. Toss the pieces in the coating until fully covered, then shake off the excess.

First fry at 325°F. In a heavy 5- to 7-quart pot, heat the oil to 325°F (165°C) over medium heat. Fry in batches without crowding until the coating is pale golden and the thickest piece reads at least 165°F (74°C): about 6 to 8 minutes for whole wings, 4 to 6 minutes for drumettes, flats or boneless thigh pieces. Drain on a wire rack.

Rest. Let the chicken rest on the rack for 5 to 10 minutes while the oil climbs to 375°F (190°C).

Second fry at 375°F. Fry again in batches for 1 to 3 minutes, until deep golden and the coating sounds hollow when tapped with tongs. Return to the rack.

Make the sauce. In a small saucepan over medium heat, whisk the gochujang, honey, soy sauce, rice vinegar, garlic, ginger and sesame oil until smooth and slightly thickened, 2 to 3 minutes.

Toss and serve. Toss the hot chicken in the warm sauce until evenly coated. Sprinkle with the sesame seeds and green onions and serve right away. Never leave hot oil unattended, and let it cool completely before straining.