1 1/2 c. thoroughly degreased fresh or canned chicken stock or water
1 1/2 c. dry white wine
3 sliced shallots or scallions
3 celery tops with leaves, cut in 2" pieces
4 parsley sprigs
1 bay leaf
10 whole peppercorns
2 lbs. whole bay scallops or sea scallops, cut into 1/2" slices

SAUCE PARISIENNE:

4 tbsp. butter
5 tbsp. flour
3/4 c. milk
2 egg yolks
1/4-1/2 c. heavy cream
A few drops lemon juice
1 tsp. salt
White pepper
1/4 c. grated imported Swiss cheese

Preheat the oven to 375°F.

In a heavy 3 to 4 quart saucepan bring the stock with shallots, celery, parsley, bay leaf and peppercorns to a boil over high heat. Reduce the heat and simmer, uncovered for 20 minutes. Strain this bouillon through a sieve into a 10" to 12" enameled or stainless steel skillet and the scallops and mushrooms. Cover and simmer for 5 minutes. Transfer the scallops and mushrooms to a large mixing bowl. Add wine and quickly boil the remaining bouillon down into 1 cup.

Sauce Parisienne: In a 2 to 3 quart enameled or stainless steel saucepan melt 4 tablespoons of butter over moderate heat. When the foam subsides, lift the pan from the heat and stir in the flour. Return to low heat and cool, stirring constantly for 1 or 2 minutes. Don't let the roux brown.

Remove the pan from the heat and slowly pour in the reduced poaching liquid and the milk whisking constantly. Return to high heat and cook, stirring the sauce with a whisk. When it thickens and comes to a boil, reduce the heat and let it simmer slowly for 1 minute.

Mix the egg yolks and 1/4 cup cream together in a small bowl and stir into it 2 tablespoons of the sauce, then whisk the now heated egg yolk and cream mixture back into the remaining sauce in the pan. After 30 seconds remove from heat, bring the sauce to a boil, stirring constantly and boil for 30 seconds.

Remove from heat and season with lemon juice, salt and pepper. The sauce should coat the spoon fairly thickly; if it is too thick thin it with more cream.

With a bulb baster, draw up and discard any juices that may have accumulated under the scallops and mushrooms. Then pour in about 2/3 of the sauce Parisienne and stir together gently. Butter 6 scallop shells, set on a baking sheet or in a broiler pan or 6 shallow 4" baking dishes and spoon the scallop mixture into them. Mash with the remaining sauce and sprinkle with cheese.

Bake the scallops in the top 1/3 of the oven for 10 to 15 minutes or until the sauce begins to bubble then slide them under a hot broiler for 30 seconds to brown the tops if desired.

Serve at once.