Preparation / Directions:
Melt margarine in a small saucepan over low heat. Add onions and celery; sauté until tender. Stir in flour, sat and pepper; cook 1 minutes stirring constantly. Gradually add milk; stir well.
Cook over medium heat until thickened and bubbly, stirring constantly. Add shredded Swiss cheese; reduce heat and cook until cheese melts, stirring constantly. Set aside.
Arrange fillets in a single layer in a 10 x 6 x 2 inch baking dish coated with cooking spray. Pour cheese mixture evenly over fillets.
Cover and bake at 350F for 25 minutes or until fillets flake easily when tested with a fork. Sprinkle with parsley..