01 - In a mixing bowl, whisk together soy sauce, sesame oil, honey, brown sugar, rice vinegar, garlic, ginger, gochujang, sesame seeds, spring onions, and black pepper until well combined.
02 - Place chicken thighs in a large resealable bag or shallow dish. Pour the marinade over the chicken and toss to coat thoroughly. Marinate for at least 30 minutes, or up to 8 hours in the refrigerator for deeper flavor.
03 - Preheat oven to 425°F. Line a baking tray with aluminum foil or parchment paper.
04 - Remove 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, turning once halfway through, until the chicken is caramelized and reaches an internal temperature of 165°F. For extra caramelization, broil for 2 to 3 minutes at the end.
06 - Let the chicken rest for 3 to 5 minutes. Garnish with toasted sesame seeds and sliced spring onions before serving.