Thaw fish fillets, if frozen. Place in a single layer on greased rack of an unheated broiler pan. Tuck under any thin edges to make even thickness.
Combine butter and lemon juice; brush over fillets. Sprinkle with salt and pepper.
Broil fish 4 inches from the heat for 10 to 12 minutes or just until fish flakes easily when tested with a fork, brushing occasionally with lemon-butter mixture. Garnish with parsley and lemon wedges. If desired, serve with hot boiled potatoes. Makes 6 servings.