Preheat oven to 425 degrees F. Line a baking sheet with parchment paper.
In a medium bowl, combine the panko, parmesan cheese, lemon zest, garlic powder, parsley, salt and pepper. Add the olive oil and toss to combine.
Arrange the cod fillets on the baking sheet and season all over with salt and pepper. Divide the panko topping among the fillets, pressing lightly so that it adheres.
Place in the oven and bake for 10-12 minutes or until the topping is lightly browned and the fish is mostly opaque (just cooked through), with a trace of translucence in the center (cut into a piece to check). Cooking time will depend on the thickness of the fillets. Serve immediately.