Marinate the Chicken: In a mixing bowl, whisk together soy sauce, brown sugar, honey, gochujang, rice vinegar, sesame oil, minced garlic, grated ginger, and sesame seeds. Add the chicken thighs and coat fully. Refrigerate for at least 20 minutes or up to 2 hours.

Make the Cabbage Slaw: Combine shredded green and red cabbage with julienned carrot. In another bowl, whisk mayonnaise, rice vinegar, sugar, salt, and pepper. Pour the dressing over the cabbage mixture and toss to coat. Chill until ready to serve.

Cook the Chicken: Heat a skillet or grill pan over medium-high heat. Remove chicken from marinade and cook for 6-7 minutes on each side, or until internal temperature reaches 165°F. Let rest for 5 minutes.

Toast the Buns: Spread butter on the cut sides of the buns. Toast in the skillet for 2-3 minutes until golden brown.

Assemble the Sandwich: Place cooked chicken on the bottom half of each bun, drizzle with more BBQ sauce if desired, and add cabbage slaw. Cap with the top bun and serve immediately.