In a large bowl, whisk together soy sauce, brown sugar, honey, gochujang, rice vinegar, sesame oil, minced garlic, fresh ginger, and toasted sesame seeds until smooth.

Add the chicken thighs to the mixture, ensuring they're well coated. Cover and marinate for at least 20 minutes at room temperature or up to 2 hours in the fridge.

Combine the shredded green and red cabbage with the julienned carrot in a large mixing bowl.

In a small bowl, whisk mayonnaise, rice vinegar, sugar, salt, and pepper until creamy. Pour over the cabbage mixture, tossing until evenly coated.

Chill the slaw in the refrigerator until ready to assemble the sandwiches.

Heat a cast-iron skillet or grill pan over medium-high heat, adding a light drizzle of oil.

Cook the marinated chicken thighs for 6-7 minutes on each side until charred and juices run clear. Let rest for 5 minutes before slicing.

Split each sandwich bun, butter the cut sides generously, and toast them butter-side-down in a skillet or under the broiler for 2-3 minutes until golden brown.

Start with a toasted bottom bun, layer it with sliced, cooked chicken, drizzle with BBQ sauce if desired, top with cabbage slaw, and finish with the top bun.