As cooks may already know, gratin is the generic French term for preparations (often involving vegetables and some sort of binding sauce) cooked in a baking dish in the oven until the surface browns and becomes crusty.
But it is also a colloquial expression that refers to a social elite, an exclusive crowd who distinguish themselves by their social background, their wealth, their elegance, and/or the select field they work in. It is generally used humourously - with a little contempt - by people who are not a part of that circle.
A close equivalent would be the English idiom the upper crust (before it became a popular name for pizzerias).
Though it was originally a matter of social class only, usage of this expression now extends to one’s connections, talent (perceived or real), and popularity: an up-and-coming artist, for instance, can belong to the gratin without being particularly wealthy (yet.) Because of this, the term is often qualified further to specify the traits of the group in question: le gratin du cinéma for the movie crowd, le gratin parisien for the Parisian high society, le gratin mondain for socialites, etc.
It is frequently used with tout (tout le gratin = all the gratin, the whole gratin), which serves to point out that these groups tend to adopt a herd behavior.
This expression with today's meaning appeared in the 19th century. It plays on the idea that the browned top of the gratin is the most flavorful, likening the social elite to this coveted part of the dish, while the rest of society lies underneath.
Note that 2 other French expressions use the same concept: la crème (the cream, which we all know rises to the top) and le dessus du panier (the top of the basket), both of which are equivalent to the English idiom the cream of the crop. You can also hear le haut du gratin to describe the top of the top, or la crème de la crème.
Ironically, le gratin was originally the word for the browned scraps of food that stick .....to the bottom of the baking dish. You would have to scrape them off, or gratter in French. What a spectacular example of social ascension! Next time you need inspiration, think of a gratin - any type of gratin will do. It rose from the bottom to the top, so can you!
Je suis allée à sa conférence, tout le gratin de la presse était là.
I went to her talk, the whole cream of the press was there.
C’est le lieu incontournable de tout le gratin parisien.
It’s the number-one hotspot for all the Parisian upper crust.
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