Cookie sheets come in all types of composition and shape and you can choose a cookie sheet by how it bakes up cookies or the look it gives to the kitchen. Some cookie sheets are better suited for darker cookies, while others bake cookies light and crisp. Read recipes carefully, as most will state which to bake the cookies on for best results.
Nonstick cookie sheets are the most common, and some can be very inexpensive. Choose by the composition of the nonstick finish and by the color. Darker finishes will bake cookies darker and lighter finishes will produce lighter colors in cookies after baking.
Nonstick cookie sheets will bake cookies quicker than other varieties but can bake them drier as well so don't overbake them. Clean up is easy but after each cleaning check the surface to ensure the finish is still intact before using and replace when the nonstick finish begins peeling.
Aluminum cookie sheets come in different styles such as rolled edges, edgeless and very high sides. Aluminum cookie sheets bake cookies uniformly since the aluminum metal properties conduct heat well. Highly acidic cookie doughs can have a negative reaction and produce a metallic flavor once the cookies are baked, so a silicone baking sheet is recommended as a barrier during baking. Cookie sheets made with a thicker aluminum will hold heat better than thinner ones and will keep cookies warmer longer once removed from the oven.
Insulated cookie sheets are those that have a thin layer of air, or a hollow space between two metal layers. Baking cookies on these sheets are best reserved for very delicate and lace-style cookies since they tend to bake slowly and require less browning.
If you use insulated cookie sheets for baking with standard cookie dough, remove them as soon as they brown around the edges or they will overbake and become hard. Insulated cookie sheets are great for cut out sugar cookies since they keep the cookies lightly colored even after baking.
Black steel cookie sheets are thick, heavy sheets and need to be seasoned before and after every use. Since black steel is a good heat conductor, cookies baked on these will bake evenly but also very dark. They are good for baking cookies that are dark and crisp and will bake rolled cookies with dark edges. These pans may require a light oiling for best removal once you finish baking the cookies. If once you have tested a cookie and it browns too quickly, reduce the heat by 25 F for better results.