An éclair is the French pastry made from choux dough, filled with cream, and coated with icing, traditionally chocolate.
Choux pastry is made by cooking flour with water or milk and butter, then beating in eggs. Steam generated during baking makes the dough expand into a hollow, elongated shell. After cooling, the shell is filled with pastry cream, crème pâtissière, or another cream filling.
The classic chocolate éclair combines vanilla or chocolate pastry cream with chocolate fondant or icing. Coffee and fruit variations are also common in modern pâtisserie.
The pastry’s name means “flash” in French, often explained by the speed with which it is eaten, although the exact origin of the name is uncertain. Éclairs belong to the same choux-pastry family as profiteroles, but their long shape distinguishes them.