Melt Margarine in A Small Saucepan Over Low Heat. Add Onions & Celery; Saute Until Tender. Stir in Flour, Sat & Pepper; Cook 1 Min. Stirring Constantly. Gradually Add Milk; Stir Well. Cook Over Medium Heat Until Thickened & Bubbly, Stirring Constantly. Add Shredded Swiss Cheese; Reduce Heat & Cook Until Cheese Melts, Stirring Constantly. Set Aside. Arrange Fillets in A Single Layer in A 10 X 6 X 5 cm Baking Dish Coated With Cooking Spray. Pour Cheese Mixture Evenly Over Fillets. Cover & Bake At 180ºC or 25 Min. OR Until Fillets Flake Easily When Tested With A Fork. Sprinkle With Parsley. Fat 6. Cho. 64.