The French pastry made from choux dough and filled with cream is an éclair.
An éclair is made by piping choux pastry into an oblong shape and baking it until crisp and hollow. Once cooled, it is filled with pastry cream, whipped cream, or chiboust cream, then topped with icing—most famously chocolate or coffee-flavored fondant.
The pastry developed in 19th-century France. It was previously known as pain à la Duchesse (“Duchess-style bread”) or petite duchesse, names that remained in use until about 1850. The word éclair means “flash of lightning” in French; explanations for the name include how quickly the pastry is eaten and the shine of its icing.
An éclair is often confused with a profiterole because both use choux pastry. The key distinction is shape: éclairs are generally long and oblong, while profiteroles are round. A similar round French pastry filled with cream is called a religieuse.