Baking sheets are flat and resilient sheets of regular or nonstick aluminum or tinned steel, with a raised rim all around or just on one edge. Use for baking cookies and pastries; roasting chiles and bell peppers; toasting bread crumbs, nuts, and coconut; shaping, transporting, and baking pizza; and much more. Dark, heavy-duty metal sheets conduct heat well for faster, more even browning; shiny, insulated sheets prevent thin or delicate cookies from browning too quickly. Baking sheets are also called baking trays.