I had a reader who wanted to know the benefits of using parchment paper. I could go on and on because I am a longtime fan of the kitchen product when baking.
First, parchment paper for baking comes bleached (white) or unbleached (brown). It is paper that has been infused with either cellulose or silicone to be heat-resistant and waterproof. Easy-to-find brands include Reynolds and Wilton. (I have always used the less expensive white paper.)
I use it whenever I bake cookies. Not only does it keep my pans clean, but it prevents spreading of dough, so baked goods rise higher and keep their shape, and baked goods slide right off the sheet. This is especially helpful when making shaped sugar cookies. (There’s no need to use fresh parchment paper for each batch, either; I reuse mine until I’m done baking, wiping down if necessary or flipping to the other side. I know home bakers who clean sheets off, fold them and freeze them for later use.)
You can cut a round and put it on the bottom of your layer cake pan, spring-form pan or pizza pan for easy removal.
Plus, there are other places to use parchment paper beside the oven. Paperchef.com says: A parchment paper-lined frying pan is particularly good for cooking eggs, including fried and scrambled. Simply line your pan and drop the eggs directly onto the paper. No grease necessary.
This method is also great for cooking bacon because it keeps the bacon flat. Lining your pan will also help to prevent burning and sticking, making for easier clean-up.
An alternative: If all you want to do is line a flat tray, buy a silicone nonstick baking mat such as a Silpat. This silicone-based, heat-resistant baking sheet is usually a better alternative than parchment paper and produces the same results.