Baked Flounder with Mozzarella cream sauce

I found this recipe online last week and had it last night. It was so good I had to share! Now these measurements are for 3 people....hope you like it!

6 flounder fillets (or any white fish)
1/4 cup red onions, chopped
1/4 cup sweet green bell peppers, chopped
3 tablespoons butter (I use Smart Balance Light with Flax)
3 tablespoons whole wheat flour
salt and pepper
1 teaspoon fresh tarragon or dry
1 teaspoon fresh basil or dry
1/2 cup fat-free milk
3 tablespoons Light Sour Cream---(this wasn't included in the original recipe but I found it made it creamier)
3/4 cup 2% reduced fat mozzarella cheese, shredded

Directions:
Prep Time: 10 mins
Total Time: 35 mins
1 Saute the onions and bell pepper in butter until the vegetables soften.
2 Add flour, salt, pepper, tarragon, basil, and milk, stirring until blended.
3 Cook sauce until it thickens, stirring constantly.
4 Lower the heat and add light sour cream and mozzarella cheese, stirring until the cheese just melts. Do NOT boil the cheese or it will get stringy.
5 Rinse the flounder fillets in cold water, then drain and pat dry.
6 Arrange the fish in a single layer in an oblong baking dish.
7 Spoon the sauce over all.
8 Bake at 425ºF for 8 to 10 minutes or until the fish flakes easily when tested with a fork.