Preparation:
combine vinegar, green peppercorns, and shallots in a saucepan, over a moderately-high flame bring to a boil and simmer until reduced to 2 tablespoons add cream and creole mustard bring to a boil, reduce heat, and simmer for 2 minutes combine 2 tablespoons butter and flour-knead to a soft paste break into small pieces and quickly whisk into sauce, one at a time heat and stir vigorously until thickened, without boiling strain through a fine chinois cover with a layer of melted butter, to keep a skin from forming cover and keep warm by placing over, not in, a water bath |