Cook lobster according to directions for steamed lobster. Pick meat from shell and claws. Melt butter or margarine in top of double boiler; add lobster and cook uncovered over low heat for 3 minutes. Add seasonings and sherry. Beat egg yolks slightly, add milk and blend thoroughly. Gradually, add the mixture to the lobster, while stirring. Cook until thickened, stirring constantly. Serve immediately on hot toast, in patty shells or toast cups.