Combine mustard, syrup, vinegar, salt & pepper in a small bowl; mix well.
Pour into a shallow glass dish.
Add salmon; turn to coat.
Cover and marinate in refrigerator 20 minutes.
Remove salmon; save marinade.
Place salmon (skin side down) on a broiler pan coated with cooking spray.
Cook 5 to 6 minutes (according to thickness) and turn.
Remove skin and discard.
Brush salmon with marinade.
Continue broiling 4 to 6 minutes, or until fish flakes easily when tested with a fork.
Baste occasionally with marinade.
Per serving: 167 calories, 25g. protein, 6g. fat.
Makes 4 servings. Prep time: 5 minutes; cooking time: less than 15 minutes; marinating time 20 minutes.