01 - Pat the chicken thighs completely dry using paper towels to ensure proper seasoning adhesion and crisp skin development.
02 - Whisk together olive oil, apple cider vinegar, brown sugar, smoked paprika, garlic powder, onion powder, chili powder, salt, and black pepper in a large bowl until the sugar dissolves and spices are evenly distributed.
03 - Add the chicken thighs to the bowl and toss thoroughly to coat each piece evenly with the spice mixture. Allow to marinate for a minimum of 15 minutes, or up to 4 hours refrigerated for deeper flavor penetration.
04 - Preheat grill to medium-high heat or set oven to 400°F, ensuring proper temperature for achieving crispy, well-cooked chicken.
05 - Place chicken thighs skin-side down on the preheated grill. Cook for 6 to 7 minutes until the skin is well-marked and crispy. Flip each thigh and brush generously with barbecue sauce.
06 - Continue grilling for an additional 25 to 30 minutes, turning and basting with more barbecue sauce every few minutes, until the internal temperature reaches 175°F and the exterior is lightly caramelized and charred.
07 - Arrange marinated chicken thighs on a foil-lined baking sheet, skin-side facing up. Roast for 30 to 35 minutes, brushing with barbecue sauce every 10 minutes, until the skin is caramelized and the internal temperature reaches 175°F.
08 - Remove the cooked chicken from the heat and let rest for 5 minutes to allow the juices to redistribute throughout the meat. Serve with additional barbecue sauce on the side if desired.