Generously coat both sides of each cod fillet with the blackening spice, about 1 tablespoon per piece of fish. Press the spices into the fish so each piece is entirely coated.
Heat the oil in a large skillet over medium-high heat. The oil should cover the entire pan. The skillet is ready when you flick in a bit of water and it sizzles immediately.
Place the cod into the skillet, and cook for 4 minutes. Flip and cook for 2 to 3 minutes until the thickest part of the fish reaches 145 F degrees. Serve immediately, garnished with chopped parsley and fresh lemon wedges.
Refrigerate in an airtight container for 2 to 3 days.
Leftovers can be eaten cold on a salad or reheated.