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, tossing to coat every piece evenly. Marinate for at least 30 minutes at room temperature, or refrigerate for 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 for easy cleanup.
04 - Remove the chicken thighs from the marinade, shaking off any excess liquid. Arrange them in a single layer on the prepared baking tray, ensuring space between each piece for even roasting.
05 - Roast the chicken for 22 to 25 minutes, flipping each thigh once halfway through the cooking time. The chicken is done when the exterior is deeply caramelized and the internal temperature reaches 165°F. For additional char and caramelization, broil for 2 to 3 minutes at the end of roasting.
06 - Allow the chicken to rest for 3 to 5 minutes after removing from the oven. Transfer to a serving platter and garnish with toasted sesame seeds and sliced spring onions before serving.