Take parsley, scallions, mushrooms, and the garlic, the whole shred fine; turn it a few times over the fire with butter; shake in a little flour, and moisten it with good broth: when the sauce is consumed to half the original quantity, add the gherkins cut small, and the yolks beaten up with some more broth; a little salt and cayenne will complete the sauce.
The Lady's Own Cookery Book (1844).