01 - Pat the chicken thighs dry with paper towels to remove excess moisture for better seasoning adhesion.
02 - In a large bowl, combine olive oil, apple cider vinegar, brown sugar, smoked paprika, garlic powder, onion powder, chili powder, salt, and black pepper. Whisk until the brown sugar dissolves completely.
03 - Add chicken thighs to the bowl and toss thoroughly to coat all pieces evenly. Let marinate for at least 15 minutes, or refrigerate for up to 4 hours for deeper flavor penetration.
04 - Preheat grill to medium-high heat or preheat oven to 400°F. If using the oven, line a baking sheet with foil for easier cleanup.
05 - Place chicken thighs on the grill skin-side down. Cook for 6 to 7 minutes until the skin is crisp and releases easily from the grates.
06 - Flip the chicken and brush generously with barbecue sauce. Continue grilling for 25 to 30 minutes, turning occasionally and basting with additional sauce each time. Cook until internal temperature reaches 175°F and the exterior is lightly charred.
07 - Arrange marinated chicken on the prepared baking sheet skin-side up. Roast for 30 to 35 minutes, brushing with barbecue sauce every 10 minutes during cooking. The chicken is done when it reaches an internal temperature of 175°F.
08 - Remove chicken from heat and let rest for 5 minutes. This allows juices to redistribute throughout the meat for maximum tenderness. Serve with extra barbecue sauce on the side.