Parsley

"Parsley" is the common name of an edible green plant, whose scientific name is Petroselinum segetum, that is frequently used, fresh or dried, as a garnish or as an ingredient in various recipes. Figuratively, and arising from the use of fresh parsley sprigs as garnishes on plates of food, "parsley" means extra features that make something more attractive, rather than making it function better; synonyms for this usage include "lagniappe," "gravy," and "bells and whistles."

"Fool's Parsley" is not parsley, just as "Fool's Gold" is not gold.