Preheat the oven to 400°F (200°C).
Pat the chicken thighs dry with paper towels.
In a small bowl, combine the Cajun seasoning, smoked paprika, garlic powder, onion powder, thyme, oregano, cayenne pepper (if using), salt, and black pepper.
Rub the chicken thighs with olive oil, then coat them evenly with the seasoning mixture.
Heat a large oven-safe skillet over medium-high heat.
Sear the chicken thighs for 4 to 5 minutes per side until nicely browned.
Transfer the skillet to the preheated oven and bake for 10 to 12 minutes, or until the chicken reaches an internal temperature of 165°F (74°C).
Remove the skillet from the oven and let the chicken rest for 5 minutes.
Garnish with chopped fresh parsley and serve with lemon wedges if desired.