Melt the butter in a skillet on medium heat, add scallops, lemon zest and garlic.
Cook stirring occasionally until scallops are just cooked through, add dill and remove from heat.
Allow to cool to room temperature.
Add Swiss cheese, mayonnaise, egg whites, bread crumbs, salt and pepper, stir to combine.
Refrigerate for two hours to allow flavors to marry.
Place a tablespoon of the scallop mixture on each of the slices of French bread.
Bake in a 375 degree oven for 12 minutes or until scallops rise and turn golden brown.
Remove from oven and place on a serving plater
Sprinkle with fresh grated parmesan cheese.
Garnish with lemon slices and fresh dill sprigs.