Pat chicken pieces completely dry with paper towels and trim any excess fat.

Combine Dijon mustard, vinegar, Worcestershire sauce, and thyme in a large ziplock bag. Add chicken, seal, and shake to coat. Refrigerate for at least 4 hours or up to 24 hours. Drain chicken before grilling and reserve the marinade.

Preheat grill to high heat. Set up one side for indirect heat by turning off one burner on a gas grill or pushing coals to one side on charcoal.

Place chicken skin-side down over direct high heat. Close lid and sear for 3 to 5 minutes until skin is golden with visible grill marks.

Flip chicken and move to the indirect heat zone. Reduce active burner to medium-low, targeting 250 to 275 degrees F. Close lid.

Cook for 30 to 50 minutes depending on thickness, brushing with reserved marinade every 10 to 15 minutes. Chicken is done when internal temperature reaches 165 degrees F.

Optional: Quickly sear the unseared side over direct high heat for 1 to 2 minutes before serving.

Pour remaining marinade into a small saucepan with 2 tbsp molasses. Bring to a boil then reduce to low simmer for 3 to 5 minutes until slightly thickened. Serve alongside the chicken.