01 - Preheat oven to 400°F. Lightly grease a baking dish large enough to accommodate the fillets in a single layer.
02 - Pat haddock fillets dry with paper towels and arrange them in the prepared baking dish. Brush the tops with melted butter.
03 - In a medium bowl, combine breadcrumbs, parsley, lemon zest, Parmesan, salt, pepper, and olive oil. Mix until the crumbs are evenly moistened.
04 - Spoon and gently press the breadcrumb mixture onto the tops of the fillets, covering them evenly.
05 - Bake for 15 to 18 minutes, or until the fish flakes easily with a fork and the topping is golden brown.
06 - Serve hot, garnished with lemon wedges.