1. Place butter in a 1-cup glass measure.
2. Microwave at HIGH for 30 seconds or until butter is melted.
3. Stir in lemon juice. Sprinkle fillets with salt and pepper; brush both sides of each with butter mixture.
4. Gently dredge fillets in breadcrumbs, and sprinkle with paprika.
5. Arrange fillets in a 12x8x2" baking dish with thicker portions to outside (thinner portions may overlap if necessary).
6. Cover with waxed paper. Microwave at High for 3 to 5 minutes or until fish flakes easily when tested with a fork, giving dish one half-turn during cooking.
7. Garnish with lemon slices and parsley, if desired.