Pat the salmon fillets dry with paper towels. This helps the spice mixture adhere better and promotes proper blackening. Leave the skin on as it helps hold the fish together during cooking.

In a small bowl, combine paprika, onion powder, garlic powder, cayenne pepper, thyme, oregano, black pepper, and salt. Mix thoroughly until well blended.

Pour the melted butter into a shallow dish. Dip each salmon fillet in butter, then generously coat with the spice mixture on all sides except the skin. Press the spices gently to adhere.

Place a cast-iron skillet over high heat until it's extremely hot (about 5-7 minutes). The pan should be smoking slightly. Good ventilation is recommended for this step!

Carefully place the salmon fillets in the hot skillet, flesh side down (skin side up). Cook for approximately 2-3 minutes until a dark crust forms. Flip the fillets and cook for another 2-4 minutes until the salmon is cooked through but still moist inside.

Remove salmon from the skillet and let rest for 2 minutes. Serve hot with fresh lemon wedges to squeeze over the top.