An apple pie is a fruit pie (or tart) in which the principal filling ingredient is apples. It is sometimes served with whipped cream or ice cream on top. Pastry is generally used top-and-bottom, making it a double-crust pie, the upper crust of which may be a circular shaped crust or a pastry lattice woven of strips; exceptions are deep-dish apple pie with a top crust only, and open-face Tarte Tatin.