Melt half of the butter in a sauté pan. Add scallions. Place pompano fillets on top. Cover, and steam for 3 to 5 minutes. Add the white wine, sherry, salt, and pepper.
Cook until pompano is firm. Transfer fish to a pan and keep warm. To the same pan, add the cooked sliced shrimp and crabmeat. Stir in the sauce. Bring to a boil. Adjust seasonings.
Cut the parchment paper into six heart shapes, about 14 inches (35 cm ) wide. Oil one side of paper.
Place two tablespoons of seafood on right side of hearts. Top each with pompano, 2 tablespoons of sauce and fold left half of heart. Roll edges to seal.
Bake in a 400 degree oven until bags puff. Serve hot with remaining cream sauce.