Prepare the oven and baking pan. Preheat the oven to 400°F. Lightly grease a baking dish or line a rimmed baking sheet with foil.
Dry the cod. Pat each cod fillet dry with paper towels. If any thin fillets were folded before freezing, gently unfold them after thawing if they separate easily without tearing.
2 pounds cod fillets
Make the seasoning blend. Add the paprika, Italian seasoning, garlic powder, onion powder, salt, black pepper, and lemon zest to a small bowl. Stir until evenly combined.
1 teaspoon paprika, 1 teaspoon Italian seasoning, ½ teaspoon salt, ½ teaspoon garlic powder, ½ teaspoon onion powder, ½ teaspoon freshly ground black pepper, 1 teaspoon lemon zest
Arrange the fish. Place the cod fillets in the prepared baking dish in a single layer, leaving a little space between each piece. Position thinner pieces where they can be removed easily if they finish first.
Add the butter and seasonings. Brush the tops of the fillets with melted butter, then sprinkle the seasoning mixture generously over each piece.
3 tablespoons butter
Bake the cod. Bake uncovered for 8-12 minutes. Begin checking thinner fillets around the 8-minute mark. Thick, center-cut cod loins may need 12-15 minutes.
Check for doneness. Remove each fillet as soon as the flesh is opaque, separates easily into moist flakes, and reaches 145°F in the thickest part.
Garnish and serve. Sprinkle the baked cod with chopped parsley and serve immediately with fresh lemon wedges.
2 tablespoons chopped fresh parsley, Lemon wedges