The parchment is for convenience and easy cleanup, mostly, although it does mitigate the bottom-browning a little. You could bake them on an inverted cake pan, for example, although it might not be ideal. Line the bottom of the the baking sheets with the aluminum foil or rice paper. I generally use butter or oil and flour. The rice paper can be placed on the baking sheets without being greased. This depends on the cookie you are baking. Spoon the batter onto the baking sheets. Some cookies just need the paper (or a silpat) as no amount of grease will allow them to release easily. Grease the baking tray and then sprinkle with plain flour, make sure it's spread all over the tray and shake off the excess. If your pans have non-stick properties they might work with shortening but I would try baking just a couple to be sure. Do not put more than a tablespoon of batter onto the spoon for each cookie. Some cookies are fine without parchment (like peanut butter). Most cookies are high in fat, so they don't stick easily, and very forgiving if you watch them closely. You can always refrigerate the dough until you can get the parchment paper if they stick badly. Place the macaroons at least 1-inch apart on the baking sheets. So if you love crispy, brown-bottomed cookies, by all means, keep reaching for the aluminum foil. – SAJ14SAJ Dec 10 '12 at 14:47 But if you're on a quest to bake the perfect batch of chocolate chip cookies (or any other cookie variety you like), it's time you listened to science: Ditch the aluminum foil, and instead make parchment paper your new cookie baking secret weapon.