A chocolate cookie crust is a no-bake or lightly baked pie and tart base made from crushed chocolate cookies or wafers mixed with melted butter, then pressed into a pan and chilled or baked to set. It differs from a chocolate crust made from rolled pastry dough, since it uses crumbs rather than a dough. It is commonly used under cream pies and cheesecakes, where its crisp, chocolatey base contrasts with a smooth filling; chocolate sandwich cookies and chocolate graham crackers are the most common bases, sometimes with added sugar, spices, or nuts.