01 - Preheat the oven to 400°F. Lightly grease a baking dish large enough to hold the haddock fillets in a single layer.
02 - Pat the haddock fillets dry with paper towels and arrange them in the prepared baking dish. Season lightly with salt and pepper.
03 - In a bowl, combine the melted butter, breadcrumbs, parsley, lemon zest, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Mix until the breadcrumbs are evenly coated.
04 - Spread the breadcrumb mixture evenly over the haddock fillets, pressing gently so it adheres.
05 - Bake in the preheated oven for 18 to 20 minutes, or until the fish flakes easily with a fork and the breadcrumb topping is golden brown.
06 - Serve immediately with lemon wedges on the side.