Bring the cream to a simmer in a deep saucepan over medium high heat. Don't use a shallow pan. The cream will climb the sides of the pan as it approaches the boiling point.
Add the Creole seasoning, salt, parsley, chives, and lemon zest. Turn the heat to medium and let simmer, stirring frequently, until the cream has thickened a bit. Preheat the broiler.
Add the shrimp and cook for 3 or 4 minutes. Carefully fold in the crab. Remove the saucepan from the heat.
Add the sherry adnd the cheese. Stir in the cheese very gently until the cheese is melted. Taste and adjust seasoning if necessary. Pour the mixture into the baking dish of your choice--ramekins, casserole dishes, etc.
Toss the melted butter with with the crumbs. Sprinkle over the top of the seafood mixture. Broil for several minutes until the crumbs are nicely browned. Serve hot.
