1 1/4  pound         flounder or sole fillet
                        --(1/8 inch to 1/4 inch thick)
     1/4  cup           balsamic vinegar
     1/4  cup           lemon juice
   1      teaspoon      dried mustard powder
   1      small         yellow onion -- chopped
   2      teaspoons     fresh
                        --or 1 tsp dried parsley
                        lemon slices -- optional
Rinse and pat dry fish fillets. Place fish in 10-inch by 8-inch oven-proof
glass or stainless steel baking dish. Combine vinegar, lemon juice, dried
mustard powder, and chopped onion in a small mixing bowl. Pour over fillets.
Cover dish and marinate fish in refrigerator for approximately 2 hours.
Preheat broiler. Remove cover from dish and place dish in broiler for
approximately 4 to 6 minutes, or until fish is white and flaky throughout.
Garnish with parsley and onion slices.
Serving size: 4 ounces
Calories per serving: 140
Per-serving composition: 4 very lean protein (courtesy of Lou Aronne, M.D.
and Kathy Isoldi, R.D. from Weigh Less, Live Longer)