Coat both sides of the fish fillets with the blackened seasoning mix, shaking off any excess spices. I like to coat the sides of each cod fillet too to ensure the whole fillet is well coated.
Heat remaining 2 tablespoons of oil in a large heavy bottomed non-stick skillet or cast-iron skillet over medium high heat. Cook for 3-5 minutes, or until the rub starts to turn black.