Either cod or flounder are good local choices for the fish mousse — almost any firm, fresh white fish will do. Naturally one would not choose expensive striped bass; that would be like making hamburgers out of ground filet mignon. You can easily buy fresh oysters already shucked, or you could substitute scallops or poached shelled shrimp for the garnish. This is a good basic recipe to know, one that bears much improvisation.
Serves six.
1 1/2 lbs. cod fillets
1 tsp. salt
1/2 tsp. white pepper
Pinch of grated nutmeg
3 shallots or 1 small white onion
2 Tbsp. butter
2 egg whites (extra-large)
2 Tbsp. potato starch
1 cup heavy cream
Oyster Sauce
3 Tbsp. butter
3 shallots, minced
12 shucked oysters with juices
3 Tbsp. flour
1 cup boiling milk
Juice of half a lemon, strained
1 Tbsp. minced chives or parsley (or both)
2 egg yolks, beaten
1/2 cup heavy cream
Salt to taste
White pepper to taste
A food processor is almost a necessity for fish mousses but there was culinary life on the planet before the Cuisinart. A regular horse-and-buggy blender can handle this job, albeit in small batches. Cut the fish into one-inch pieces and put them into the processor with the salt, pepper, and nutmeg. Peel and chop the shallots or onion roughly and add them to the work-bowl. Puree until smooth (when this had to be done in a mortar and pestle, a fish mousse such as this was beyond the purview of home cooking). Butter a plain ring mold and preheat the oven to 350 degrees F. Select a pan that the ring mold will fit into and allow for a depth of one inch of boiling water.
Incorporate into the pureed fish in the following order, scraping down after each addition, one egg white, one tablespoon starch, half cup cream. Repeat the process. Scrape the mixture into the buttered mold and smooth it over the top with a rubber or plastic spatula. Cover with a piece of buttered foil. Set the ring mold into its underpan, pour in the boiling water, and place it in the center of the oven. Bake for approximately one hour.
Cook the potatoes and whatever vegetable you have chosen and make the sauce which should not be made too much in advance because the oysters will toughen.
Melt the butter and gently saute the shallots until transparent. Add the oysters and their juices and poach over low heat just until the oysters ruffle. Remove them with a slotted spoon and reserve. Stir in the flour, whisking it smooth. Pour in the boiling milk off- heat and whisk it smooth. Add half the lemon juice (be cautious as the sauce should not taste lemony), then the chives or parsley. Mix the beaten yolks with the cream and whisk this into the sauce, which must not boil after this point or the yolks might separate. Add salt and pepper to taste and more lemon juice as desired. Return the poached oysters to the sauce and warm them. Unmold the fish mousse onto a round platter and mop up the juices with tissues. Spoon the sauce evenly over the mousse and fill the center with buttered broccoli or snow peas. Asparagus will have to be served separately on its own platter unless you’re willing to cut the precious spears up into short lengths. In any event you cannot get enough vegetables for six people into the center of any ring mold I’ve ever seen so a separate vegetable dish will be needed anyway.
