The variation with sole demonstrated how nicely sherry cream sauce—a Maryland hallmark, used not just in many Marconi dishes but also in the famous crab Maryland—takes to different kinds of fish and seafood. Keith Watson, Marconi's chef, learned his recipe from Tony Sartori, the previous chef, with whom he apprenticed at the age of eighteen (Sartori, born in the northern Italian city of Piacenza, started at Marconi when he was twenty and stayed forty-two years). His description made me want to try making it. The cardinale sauce at Marconi is less elaborate than the French original, which is named for the red of cooked lobster (not, as restaurant lore has it, for a Baltimore cardinal who ate there), and usually includes lobster fumet and truffle essence. Watson instead makes a simple béchamel, flavored with sherry, paprika, and diced lobster meat, which derives a pillowy texture from the folding in of a bit of whipped cream.
I've streamlined Watson's restaurant-kitchen method, to encourage rediscovery of the sturdy versatility of simple white sauce (far less rich than today's butter-filled reduction sauces), taking a basic béchamel from Shirley Corriher's invaluable CookWise. For four portions, first chill a half cup of heavy whipping cream and a bowl and beaters. In a medium saucepan heat two cups of milk just to a simmer, stirring to be sure it doesn't scorch, and let stand off the heat for five minutes. In another saucepan make a roux: melt four tablespoons of butter, stir in a quarter cup of flour, and cook over a low flame, stirring constantly, for two to three minutes. Don't let it brown. Remove the roux from the heat and pour in the hot milk, using a strainer to get out any bits of skin. Whisk vigorously and add two teaspoons of sherry (I suggest a dry Spanish sherry; Watson uses a medium-sweet California one). Stir over medium heat until the sauce reaches a low simmer. Turn the heat very low and cook for another ten or so minutes, stirring constantly. Remove from the heat and season with salt and white pepper.
Watson turns this béchamel into a cheeseless mornay sauce by adding egg yolks; these are optional, but they provide both volume and richness. For the full effect, beat two yolks in a medium-size bowl and whisk into them a half cup of the warm (not hot) sauce. Slowly pour this mixture into the rest of the sauce, whisking all the while. Let stand at room temperature.
As final flavoring Watson adds lobster meat sautéed in butter and sherry and seasoned with paprika; this is also optional, but it makes the dish both fancier and truer to its French origins. Dice a quarter cup of cooked and picked lobster meat and sauté it in two teaspoons of butter over medium heat for a minute or two. Pour over the meat two teaspoons of sherry and a quarter teaspoon of paprika, and heat for a minute or so, just until the wine evaporates; add the meat to the waiting sauce. If you skip the lobster, add the paprika along with the salt and pepper.