1 tbsp. reduced calorie butter
1/4 c. chopped onion
1/4 c. chopped celery
12 oz. flounder fillets
1/4 c. sliced mushrooms
1/4 tsp. salt
Dash of pepper
1/2 c. orange juice
1/4 c. chopped fresh parsley
1 1/2 tsp. flour
1/2 sm. orange, thinly sliced
2 parsley sprigs

Melt 1 1/2 teaspoon butter in large non-stick skillet; add onion and celery and cook until tender. Place fillets over vegetables; top with mushrooms and sprinkle with salt and pepper. Add orange juice and bring to a boil. Reduce heat to low, and cover; simmer for 10 minutes. Add chopped parsley and simmer 5 minutes longer. Transfer fish to warmed serving platter.

Remove remaining vegetables from skillet with slotted spoon to arrange over fish. Reserve cooking liquid. Melt remaining butter in small saucepan over medium heat; stirring constantly, add flour to cook with mixture reaching boiling point. Reduce heat and add reserve liquid; cook, stirring until thickened. Pour sauce over fish and vegetables. Garnish with orange slices and parsley sprigs.