A Vol au vent is a small, round canapé

A Vol au vent is a small, round canapé made of puff pastry.
A Vol au vent (pronounced [vɔlovɑ̃], French for "windblown" to describe its lightness) is a small hollow case of puff pastry.
A round opening is cut in the top and the pastry cut out for the opening should be replaced as a lid after the case is filled.
Vol au vents can be filled with fillings, such as mushrooms, prawns, fruit, or cheese.
The pastry and its catchy name vol au vent were invented by Antonin Carême in his pastry-shop .
In Cookery it means a very light puff pastry case filled either with a savory mixture in a richly flavored sauce or sometimes with fruit.
It is said to have been created by the famous French chef Carême, a vol au vent, it is a PUFF PASTRY shell that resembles a pot with a lid.
The pastry is classically filled with a cream sauce-based mixture, usually of chicken, fish, meat or vegetables.
The puff-pastry lid is set on top of the filling.
This dish may be served as an appetizer or an entrée. 
The word ' vol au vent ,' means "flying in the wind," because
of the pastry's incredible lightness.