Cut boneless thighs into bite-size pieces and pat them dry with paper towels. Season with salt and white pepper, and optionally, a touch of garlic powder. Let sit for 10 minutes.

Mix cornstarch and flour in a bowl. Add baking powder. Toss the chicken to coat lightly, then prepare a wet batter with cold water and soy sauce.

Dip each chicken piece in the wet batter, then return to the dry coating for a thin, craggy crust.

In a pan, heat oil and sauté garlic and ginger until fragrant. Stir in ketchup, gochujang, vinegar, soy sauce, honey, brown sugar, and heat element. Simmer until thick and glossy.

Heat oil to 325°F for the first fry. Fry chicken in batches for 4-5 minutes until pale golden. Rest on a rack.

For the second fry, raise the heat to 350-360°F and fry until deep golden and very crisp, about 2-3 minutes. Toss immediately in the warm sauce.

Serve right away, garnished with sesame seeds and scallions.