A pie crust is a baked pastry shell that serves as the base for various types of pies, such as fruit, custard, or savory fillings. It is typically made from a mixture of flour, fat (like butter or shortening), and water. The dough is rolled out and placed in a pie dish, where it can be pre-baked or filled and baked together with the filling. There are two main types of pie crusts: single crust, which covers only the bottom of the pie, and double crust, which has both a top and bottom layer. The texture can vary from flaky to tender, depending on the ingredients and preparation method used.