National Pie Day takes place on January 23, 2018. A pie is a baked dish which is usually made of a pastry dough casing that covers or completely contains a filling of various sweet or savoury ingredients. Pies can be a variety of sizes, ranging from bite-size to ones designed for multiple servings.
Pies are defined by their crusts. A filled pie has pastry lining the baking dish, and the filling is placed on top of the pastry but left open. A top-crust pie, which may also be called a cobbler, has the filling in the bottom of the dish and is covered with a pastry or other covering before baking. A two-crust pie has the filling completely enclosed in the pastry shell. (With material from: Wikipedia)