01 - Preheat a large cast-iron skillet over medium-high heat until very hot (about 5 minutes).
02 - Pat chicken breasts dry with paper towels.
03 - In a small bowl, combine all spice mix ingredients: smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, black pepper, and kosher salt.
04 - Brush both sides of the chicken breasts with olive oil or melted butter. Generously coat each chicken breast on all sides with the spice mixture, pressing gently so the spices adhere.
05 - Place chicken breasts in the hot skillet. Cook undisturbed for 4–5 minutes until a dark, almost black crust forms.
06 - Flip the chicken and cook another 4–5 minutes, or until the internal temperature reaches 165°F (74°C) and juices run clear.
07 - Remove from heat and let rest for 2–3 minutes. Slice and serve hot, garnished with fresh parsley and lemon wedges as desired.