In a medium bowl, combine low-sodium soy sauce, brown sugar, honey, gochujang, rice vinegar, sesame oil, minced garlic, grated ginger, sesame seeds, and chopped green onions. Whisk until smooth. Add the boneless skinless chicken thighs, tossing until well-coated. Allow the chicken to marinate for at least 20 minutes at room temperature or refrigerate for up to 2 hours for maximized flavor infusion.

In a large mixing bowl, combine shredded green cabbage, red cabbage, and julienned carrots. In a separate bowl, whisk together mayonnaise, rice vinegar, a pinch of sugar, salt, and pepper until creamy. Pour this dressing over the cabbage mixture, tossing well to coat everything evenly. Cover and chill the slaw in the refrigerator until you’re ready to serve your Korean BBQ Chicken Sandwich.

Preheat a skillet or grill pan over medium-high heat. If needed, lightly oil the surface to prevent sticking. Once the pan is hot, add the marinated chicken thighs. Cook for about 6–7 minutes on each side, until the chicken is caramelized and reaches an internal temperature of 165°F. Once cooked, remove the chicken from the heat and let it rest for 5 minutes.

While the chicken rests, split the brioche or potato sandwich buns and lightly butter the cut sides. In the same skillet or under the broiler, toast the buns for 2–3 minutes until they are golden and crispy. Keeping an eye on them is crucial to prevent burning.

To assemble your Korean BBQ Chicken Sandwich, place a piece of the juicy chicken on the bottom bun. Drizzle with additional sauce if desired. Generously pile the crunchy cabbage slaw on top, capping it with the top bun and serve immediately.