Shrimp & Scallops Au Gratin - Puff Pastry

Ingredients

• 1 package (10 ounces) Pepperidge Farm® Puff Pastry Shells
• 1/4 cup butter(1/2 stick)
• 1/2 pound medium shrimp, shelled and deveined
• 1/2 pound scallop, cut into halves
• 1 dash ground black pepper(optional)
• 6 ounces sliced mushrooms (about 2 cups)
• 1/4 teaspoon garlic powder or 1 clove garlic, minced
• 2 tablespoons all-purpose flour
• 1 1/2 cup milk
• 1 cup shredded Swiss cheese (about 4 ounces)
• 2 tablespoons chopped fresh parsley