01 - Set oven rack to the center position and preheat to 400°F (200°C).
02 - In a large mixing bowl, whisk together olive oil, lemon juice, ground cumin, ground coriander, smoked paprika, ground cinnamon, ground turmeric, cayenne pepper if desired, minced garlic, kosher salt, and ground black pepper until fully combined.
03 - Add chicken thighs to the bowl and toss thoroughly in the marinade, ensuring all surfaces are coated. Cover and refrigerate for at least 30 minutes, or marinate overnight for deeper flavor.
04 - Line a baking sheet with parchment paper or aluminum foil. Remove chicken from marinade and arrange thighs skin-side up on the prepared baking sheet.
05 - Roast chicken in the preheated oven for 35 minutes, or until skins are crisp and internal temperature at the thickest point registers 165°F (74°C).
06 - Remove chicken from oven and allow to rest for 5 minutes. Garnish with freshly chopped cilantro and serve with lemon wedges.
07 - Present hot, accompanied by couscous, rice, or flatbread.