In a mortar and pestle (or small bowl), mash together the brown sugar, minced garlic, kosher salt, and black pepper until it forms a paste. If using, add the smoked paprika and cayenne pepper for extra flavor dimension.

Transfer the paste to a large resealable plastic bag. Add the chicken pieces and massage to coat evenly. Seal the bag, removing as much air as possible. Refrigerate for at least 1 hour, but preferably overnight for maximum flavor penetration.

Preheat your grill to medium heat (around 350-375°F). For a charcoal grill, set up for indirect cooking with coals on one side. For gas grills, turn one side to medium and leave the other side off.

Remove chicken from the marinade and lightly pat dry with paper towels. Brush with olive oil to prevent sticking. Place chicken on the indirect heat side of the grill, skin side up.

Close the grill lid and cook for about 15-20 minutes before flipping. This slower cooking helps render the fat and ensures even cooking.

After flipping, start basting with BBQ sauce. Continue cooking for another 15-20 minutes, basting occasionally with more sauce.

For the final 5-10 minutes, move the chicken to the direct heat side of the grill to caramelize the sauce and get those beautiful grill marks. Watch carefully to prevent burning!

Use a meat thermometer to ensure chicken reaches 165°F for breasts and 175°F for thighs and drumsticks. The juices should run clear, not pink.

Remove chicken from the grill and let rest for 5-10 minutes under loose foil. This helps the juices redistribute throughout the meat for maximum tenderness.

Transfer to a serving platter, brush with a final layer of BBQ sauce if desired, and serve hot with your favorite sides!