What is Choux pastry?

Choux pastry is a French specialty used for cream buns, chocolate eclairs and profiteroles. The feather-light pastry surrounds a large cavity which is filled with cream.
The dough is made from strong flour, butter, eggs, sugar and water. The butter is boiled with a water/milk mix and flour is added to it before being beaten and eggs are added. The mixture is put in a forcing bag, and placed as rounds or lengths on a baking tray .
During baking in a hot oven the water is released in the form of steam and blows out the protein and starch in the paste. Heat from the oven sets the choux into a hard empty shell. When cool, the pastry is pierced to let out the steam.