A sweet or savory dish made with a crust and filling (such as fruit, pudding, meat or vegetable). Pies can have bottom crusts only, or top and bottom crusts or, as with deep-dish pies, only a top crust. Sweet pies are generally served as dessert and savory pies as the main course or appetizer. Crusts can be made of a variety of mixtures including short crust pastry, puff pastry, cookie crumbs, meringue and even, as with shepherd'S pie, mashed potatoes. See also tart.