Parsley Butter Sauce
["3 Tbsp. finely chopped shallots", "2 Tbsp. sherry vinegar", "1/4 c. dry white wine", "1/2 c. fish broth or bottled clam juice", "1/2 c. heavy cream", "3 Tbsp. butter", "salt to taste, if desired", "freshly ground pepper to taste", "1 Tbsp. coarse or Meaux mustard", "1/4 c. finely chopped parsley"]
["Combine the shallots, vinegar and wine in a saucepan and bring to a boil.", "Cook until reduced by half.", "Add the broth and cream and bring to a boil.", "Cook at a rolling boil about 45 seconds. Swirl in the butter.", "Add the salt and pepper and stir in the mustard and parsley.", "Yields about 3/4 cup."]
["shallots", "sherry vinegar", "white wine", "fish broth", "heavy cream", "butter", "salt", "freshly ground pepper", "coarse", "parsley"]