01 - In a mixing bowl, whisk together the soy sauce, sesame oil, honey, brown sugar, rice vinegar, minced garlic, grated ginger, gochujang, toasted sesame seeds, sliced spring onions, and black pepper until fully combined.
02 - Place the chicken thighs in a large resealable bag or shallow dish. Pour the marinade over the chicken, toss to coat thoroughly, and refrigerate for at least 30 minutes or up to 8 hours for deeper flavor penetration.
03 - Preheat the oven to 425°F. Line a baking tray with aluminum foil or parchment paper.
04 - Remove the chicken from the marinade, shaking off any excess. Arrange the thighs in a single layer on the prepared baking tray.
05 - Roast for 22 to 25 minutes, flipping once halfway through, until the chicken is deeply caramelized and reaches an internal temperature of 165°F. For additional char, broil for 2 to 3 minutes at the end of roasting.
06 - Allow the chicken to rest for 3 to 5 minutes. Garnish with toasted sesame seeds and sliced spring onions before serving.