01 - Combine olive oil, smoked paprika, garlic powder, onion powder, oregano, thyme, cayenne, black pepper, salt, brown sugar, and lemon juice in a large bowl. Whisk until thoroughly incorporated.
02 - Add chicken thighs to the bowl and turn to coat completely. Cover with plastic wrap and refrigerate for a minimum of 30 minutes, up to 8 hours for optimal flavor penetration.
03 - Prepare a grill or grill pan over medium-high heat, approximately 375-400°F. Lightly oil the grates to prevent sticking.
04 - Place marinated chicken on the preheated grill. Cook for 6-8 minutes per side until internal temperature reaches 165°F and exterior shows distinct char marks.
05 - Remove chicken from heat and transfer to a serving platter. Allow to rest for 5 minutes before garnishing with fresh parsley and lemon wedges.