It was formerly also called a patty case. A vol-au-vent is typically made by cutting two circles in rolled out puff pastry, cutting a hole in one of them, then stacking the ring-shaped piece on top of the disc-haitian patties piece. The pastry is cooked, then filled with any of a variety of savory or sweet fillings.
The pastry is sometimes credited to Antonin Carême. In France, it is usually served as an appetizer or a small snack, filled with chicken or fish. In Belgium, it is a common main dish that can be found on the menus of most restaurants, and is nearly always filled with a combination of chicken, mushrooms, and small meatballs, served with either mashed potatoes or fries. In Pakistan, vol-au-vents with meat filling are called “patties”: round ones usually have a chicken filling, and rectangular ones have a beef filling. Savoury Pastry: Savoury Dish and Raised Pies, Pork Pies, Patties, Vol-au-vents, Mincemeats and Pies, and Miscellaneous Savoury Pastries. London: Office of the “Baker and Confectioner”. Cooking for Kings: The Life of Antonin Carême, the First Celebrity Chef.