In a shallow bowl or baking dish, whisk together oil, paprika, salt, dried thyme, onion powder, garlic powder, black pepper, dried oregano, and cayenne pepper.
Pat fish very dry with paper towels (this is important to help the spices to stick.) Add the fish to the spice mixture, turning to coat.
Heat a large cast iron pan to medium heat. Add butter.
When the butter melts, remove the fish from the marinade. Add the cod to the hot pan and cook on one side until a dark crust appears, 2 to 3 minutes.
Flip the cod to cook it on the other side. As the cod finishes cooking, tip the pan and spoon the spices back over the top of the fish. Continue cooking until cooked through (145°F), 2 to 3 minutes more.
Transfer the cod to a serving plate. Drizzle any remaining spices and butter from the pan over the cod.
Serve with lemon wedges for squeezing over the top.