In a medium bowl, combine gochujang, soy sauce, honey, sesame oil, minced garlic, grated ginger, rice vinegar, and black pepper. Whisk together until smooth.

Place the chicken thighs into a resealable plastic bag and pour the marinade over them. Seal the bag and massage to distribute the marinade thoroughly. Refrigerate for at least 1 hour or overnight.

Wash and chop the green cabbage and julienne the carrots. In a large bowl, mix these crunchy vegetables.

In a small bowl, whisk together mayonnaise, lime juice, and optional sriracha. Pour over the cabbage and carrot mixture and toss.

Preheat your grill pan over medium-high heat for about 5 minutes. Drizzle a bit of oil to prevent sticking.

Carefully place the marinated chicken thighs on the hot grill pan and grill for 6–7 minutes on each side, or until charred.

Once grilled, remove the chicken and let it rest for about 5 minutes on a cutting board. Slice into strips.

Slice the brioche buns in half and toast them on the grill pan for about 2-3 minutes.

To assemble, place grilled chicken strips on the bottom half of each toasted bun, top with slaw, garnish with cilantro and sesame seeds, and cap with the other half of the bun.