1. Place 1 oven rack 5 inches from heat; place a second rack in middle of oven. Combine Parmesan cheese and paprika. Season fish with salt and pepper.
2. Preheat oven to 450°. Heat butter in a broiler-safe 13- x 9-inch baking dish in oven 8 minutes or until butter is melted and beginning to brown. Place fish in hot butter, skin sides up.
3. Bake at 450° on middle oven rack 10 minutes. Carefully flip fish, and baste with pan juices. Sprinkle with lemon juice and Parmesan cheese mixture. Bake 5 more minutes or just until fish flakes with a fork. Remove from oven; increase oven temperature to broil.
4. Broil fish on oven rack 5 inches from heat 2 to 3 minutes or until bubbly and golden brown.