*Sitting in the middle of rural Morvan as they were, the hotel’s original owners had probably hoped to see a bit of gastronomic glory rub off on them from the celebrated Parisian restaurant Café Marguéry, after which they named their place. Café Marguéry became doubly famous around the turn of the nineteenth into the twentieth century for having fallen victim to one of history’s most curious acts of gastronomic espionage after the American millionaire-glutton Diamond Jim Brady heard tell of the incomparable sauce—a closely guarded professional secret—that was the highlight of filets de sole Marguéry. Under threat of refusing his future patronage, Brady persuaded the owner of one of his preferred New York restaurants to yank his son from Cornell and send him to Paris as a spy to snitch the recipe. The boy wangled a job as a dishwasher and worked assiduously enough to be promoted up into the brigade, where he learned the heart of the secret: mussels. Like most seafood sauces, this one was a reduction of a white-wine-based fish stock, but heavily flavored with a reduction of the water in which mussels had been cooked. The final liaison was done with egg yolks and, unsurprisingly, a generous scoop of fresh, soft butter. With all of Brady’s chicanery, though, it is probable that any competent cook could have doped out the broad lines of the sauce by simply going to Café Marguéry, ordering the dish, looking, and tasting. The ring of mussels ritually surrounding the poached sole would have been in itself a pretty glaring giveaway.