In a small saucepan over medium heat, combine 1 cup of ketchup, 3 tablespoons of gochujang, 2 tablespoons of white vinegar, 2 tablespoons of honey, 3 tablespoons of soy sauce, 1 tablespoon of ginger paste, and 1 tablespoon of garlic paste. Bring the mixture to a boil, then reduce the heat and let it simmer for about 5 minutes, stirring occasionally until slightly thickened. Allow the sauce to cool down as you prepare the chicken.

Take 1.5 pounds of boneless, skinless chicken thighs and place them in a gallon-size plastic bag. Pour in a few spoonfuls of the prepared Korean BBQ sauce along with kosher salt and pepper to taste. Seal the bag tightly and gently massage the chicken to ensure it's evenly coated. Refrigerate for at least 1 hour, ideally overnight.

About 15 minutes before you’re ready to grill, preheat your grill to medium-high heat, aiming for around 400°F. Ensure the grill grates are clean and lightly oiled.

Once the grill is ready, carefully place the marinated chicken thighs on the grates. Grill them for about 4-6 minutes per side, flipping when they release easily from the grill.

During the last two minutes of cooking, brush the thighs with additional Korean BBQ sauce.

After grilling, ensure the chicken has reached an internal temperature of 165°F using a meat thermometer.

Once cooked, remove the chicken from the grill and let it rest for a couple of minutes before serving, drizzling with remaining sauce.