An éclair is an oblong pastry made with choux dough filled with a cream and topped with icing. The dough, which is the same as that used for profiterole, is typically piped into an oblong shape with a pastry bag and baked until it is crisp and hollow inside. Once cool, the pastry then is filled with a vanilla-, coffee- or chocolate-flavouredcustard (crème pâtissière), or with whipped cream, or chiboust cream; and then iced with fondant icing. Other fillings include pistachio- and rum-flavoured custard, fruit-flavoured fillings, or chestnut purée. The icing is sometimes caramel, in which case the dessert may be called a bâton de Jacob.
The éclair originated during the nineteenth century in France where it was called "pain à la duchesse" or "petite duchesse" until 1850. It is a popular member of the pie family served all over the world. The word is first attested both in English and in French in the 1860s. Some food historians speculate that éclairs were first made by Antonin Carême (1784–1833), the famous French chef. The first known English-language recipe for éclairs appears in the Boston Cooking School Cook Book by Mrs. D.A. Lincoln, published in 1884.
Some pastry chains in the United States and Canada market Long John doughnuts as éclairs or éclair doughnuts. Long Johns are not identical with éclairs, as Long Johns use doughnut pastry, which is yeast-risen or batter-derived, rather than choux dough, which is steam-puffed. Long Johns are usually filled with vanilla pudding or custard and topped with cake icing.