Parchment Paper

How to Use Parchment Paper in Cooking.
Parchment paper (also know simply as “baking paper”) is a handy item to keep in the kitchen for regular use. Parchment paper can be placed on baking sheets, inside cake pans, and on other baking containers to act as a barrier between the dish and the food being baked or cooked. In this way, the food won’t stick, burn on, or be affected by the baking dish directly

Line the baking container with parchment paper. Most types of containers can be lined with parchment paper, including cookie and baking sheets (trays), baking pans and dishes, cake pans and tins, and casserole or stew dishes.

Cut parchment paper to size. To prevent wrinkling of baked goods such as cakes, pies, and slices, cut the parchment paper to fit the container properly.

Use parchment paper as a non-stick surface for chocolate and candies. As well as baking and cooking, parchment paper is an excellent surface for chocolate and candies that are setting.
Make use of parchment paper for various uses beyond the usual. Parchment paper is useful for making pastry or icing cones, for measuring foods onto, for lining food gift boxes (great for candies and cookies), and for lining storage containers. It can even line drawers if needed!
Parchment paper is great for lining baking sheets used for heating up fries and greasy foods.

This will stop the fat layer from ruining the sheet.

Source: wikihow.com