Parsley Emulsion

Few of us recognize the complex and beguiling aroma and flavor of fresh parsley. In restaurants, it is usually chopped in advance so that it loses its delicacy and takes on the smell of lawnmower clippings. Because of this, chopped parsley, parsley purées, and this emulsion must be prepared within 15 minutes of serving. Because parsley contains no starch or natural emulsifiers, any sauce based on it must use another thickener that will hold the puréed parsley in suspension—here, xanthan gum