01 - Combine olive oil, smoked paprika, garlic powder, onion powder, oregano, thyme, cayenne pepper, black pepper, salt, brown sugar, and lemon juice in a large bowl. Whisk thoroughly until all spices are evenly distributed.
02 - Add chicken thighs to the bowl and toss until each piece is completely coated with the spice mixture. Cover tightly and refrigerate for minimum 30 minutes, maximum 8 hours for optimal flavor penetration.
03 - Heat grill or grill pan to medium-high temperature. Lightly oil the grates to prevent sticking and ensure easy removal after cooking.
04 - Place marinated chicken on preheated grill. Cook for 6 to 8 minutes on the first side, then flip and continue grilling for another 6 to 8 minutes. Chicken is done when internal temperature reaches 165°F and exterior shows attractive char marks.
05 - Remove chicken from grill and transfer to serving platter. Let rest for 5 minutes to allow juices to redistribute throughout the meat. Sprinkle with fresh chopped parsley and arrange lemon wedges alongside before serving.