From the pages of Viz Comic, a "special ingredient" added by a restaurant/cafe/pub chef, solely of Y-chromosome, to a dish given to a famous and/or particularly disagreeable customer, namely a restaurant critic.
Takes its name from The Sunday Times restaurant critic and sometime film director, Michael Winner. A well-known trasher of both restaurants and chefs' reputations.
"See that Michael Winner over there? He's reckoned to have ingested more Winner's Sauce than Marc Almond"