An apple pie is a pie in which the principal filling ingredient is apple. It is often served with whipped cream, ice cream ("apple pie à la mode"), or cheddar cheese. It is generally double-crusted, with pastry both above and below the filling; the upper crust may be solid or latticed (woven of crosswise strips). The bottom crust may be baked separately ("blind") to prevent it from getting soggy. Deep-dish apple pie often has a top crust only and tarte Tatin is baked with the crust on top, but served with it on the bottom. Apple pie is an unofficial symbol of the United States and one of its signature comfort foods.