In a mixing bowl, combine paprika, cayenne pepper, garlic powder, onion powder, thyme, oregano, black pepper, and salt. Mix well.

Pat the fish fillets dry with paper towels. Coat both sides of each fillet generously with the blackening spice mix.

Heat the cast iron skillet over medium-high heat. Add butter and olive oil. Once hot, add the seasoned fish fillets.

Cook for about 3-5 minutes on each side, or until the fish is cooked through and has a blackened crust.

Remove the fish from the skillet and let it rest for a minute before serving. Enjoy with your favorite sides.