Prep the chicken: Pat drumsticks dry with paper towels. Use a sharp knife to make 2–3 shallow slashes in the thickest part of each drumstick. This helps the marinade penetrate and ensures even cooking.

Marinate: In a large bowl, mix buttermilk, soy sauce, gochujang, ginger, garlic, salt, and pepper. Add drumsticks and toss to coat. Cover and refrigerate for at least 1 hour, up to 12 hours. Longer equals deeper flavor.

Make the coating: In another bowl, whisk cornstarch, flour, baking powder, salt, garlic powder, and pepper.

Coat the chicken: Remove drumsticks from the marinade, letting excess drip off. Dredge each piece in the dry coating, pressing to adhere. Set on a wire rack for 10–15 minutes. This rest helps the crust set.

Heat the oil: In a deep pot or Dutch oven, add 2–3 inches of oil. Heat to 340–350°F (171–177°C). Use a thermometer for accuracy.

Fry in batches: Add 3–4 drumsticks at a time. Fry 10–13 minutes, turning occasionally, until golden and the thickest part reads 165°F (74°C). Adjust heat to keep oil near 345°F. Transfer to a rack to drain. Repeat with remaining pieces.

Make the sauce: While frying, combine gochujang, honey, soy sauce, rice vinegar, sesame oil, garlic, and ginger in a small saucepan. Simmer over low heat 3–4 minutes. Add water as needed to reach a thick, pourable glaze. Taste and adjust sweetness or acidity.

Toss to coat: Place fried drumsticks in a large bowl. Pour sauce over and toss until evenly glazed. Work in batches if needed so the coating stays crisp.

Finish and serve: Sprinkle with sesame seeds and scallions. Serve hot with pickled radish, steamed rice, or a crisp slaw.