Cookies do best on a shiny, light colored, aluminum baking sheet lined with parchment paper (for easy cleanup and nonstick baking). Avoid dark colored or insulated pans. They cause uneven baking and the cookies can be excessively brown. These are the only pans I use. If you only have dark colored baking sheets, adjust your temperature down by 25 degrees Fahrenheit and lessen the total baking time by a few minutes, if needed. Keep a close eye on the cookies the last 4-5 minutes to gauge doneness.