In a medium bowl, whisk together soy sauce, brown sugar, honey, gochujang, rice vinegar, sesame oil, minced garlic, and ginger until fully blended. Coat the chicken thighs in the marinade and refrigerate for 20 minutes to 2 hours.

In a large mixing bowl, combine shredded green and red cabbage with julienned carrots. In a separate bowl, whisk together mayonnaise and seasonings. Pour the creamy dressing over the cabbage mixture and toss well, chiling to let flavors develop.

Heat a skillet over medium-high heat. Remove the chicken from the marinade and cook for 6-7 minutes on each side until charred and cooked through. Let rest for 5 minutes before slicing.

In the same skillet, butter the cut sides of the buns and toast face down for 2-3 minutes until golden brown.

Assemble the sandwich by layering sliced chicken on the toasted bun, topping it with the slaw, and finishing with the top half of the bun.