Preparation / Directions:
1. Thaw frozen fish according to package directions.
2. Rub rectangular baking dish with 1 tablespoon of the butter.
3. Pat fillets dry; arrange in dish in one layer.
4. Add wine; scatter mushrooms over fish and sprinkle with salt and pepper.
5. Bake in preheated 400F oven 10 minutes.
6. Meanwhile, melt remaining 4 tablespoons butter in saucepan; add flour, stirring with whisk.
7. Add milk, stirring; when blended and smooth, remove from heat.
8. Pour liquid from baked fish into saucepan, stirring; bring to a boil and cook, stirring often, about 5 minutes.
9. Stir in lemon juice; pour sauce over fish and bake 10 minutes longer.
10. Sprinkle with cheese and parsley; serve hot.