Saute seafood and shallots in 4 tablespoons butter. Cook 5 minutes. Sprinkle with 6 tablespoons of sherry; salt and pepper. In another pan melt the remaining 3 tablespoons butter and add flour to make paste. Add milk and remaining 4 tablespoons sherry; stir until smooth. Combine sauce and seafood mixture and place in a casserole or individual ramekins. Top with bread crumbs and Parmesan. Bake at 400F for 30 minutes.