Parchment paper, also known as baking paper, is a stick-resistant, ovenproof paper used for lining baking sheets or pans, or for wrapping fish or shellfish en papillote-"in an envelope." For cookies, the paper facilitates easy removal to racks to cool, allows for preparing multiple sheets of cookies at a time, and keeps the pans clean. In some recipes, aluminum foil or waxed paper can be substituted.