• In a medium sized sauce pan, place potatoes and cover with water. Bring to a boil, add salt then lower to a simmer. Cook until potatoes are tender.

Prepare the bechamel sauce:

• In a small sauce melt the butter on medium heat. Add the flour and stir with a whisk until a paste is formed. Gradually whisk in the milk, stir and bring to a boil. Cook until the sauce is has thickened.

Prepare the seafood filling:

• Meanwhile, rinse the shrimp and scallops. Drain well and pat dry.
• In a large skillet, heat olive oil on medium heat. Add onions and sauté until softened. Add mushrooms and cook until they have released their water and it has evaporated, about 5 minutes.
• Add shrimp, scallops and cook, stirring, for 3 minutes. Add salt and pepper, to taste. Pour in white wine and cook until it has evaporated. At this point, drain the seafood if there is a lot of liquid in the pan. Tranfer seafood to a bowl.
• Pour the sauce over the seafood and stir to combine. Stir in chopped parsley.

Assemble:

• Preheat oven at 350°F. Divide the seafood among 4 scallop shells placed on a baking sheet.
• When the potatoes have cooked, mash them as desired with milk, butter or olive oil and salt. Place the potatoes in a pastry bag with star tip or in a freezer bag with the tip snipped off. Pipe the potatoes around the seafood filling.
• Top each shell with shredded mozzarella.
• Bake for about 20 minutes until the cheese is bubbling. If desired, at the end of cooking time broil for a minute or two to brown the cheese. Serve immediately.