Thermoplastic polymeric compositions have relatively high thermal conductivities, providing advantages for cooking food. These compositions can be made by mixing a thermoplastic polymer with a particulate material that has a relatively high thermal conductivity. The composition usually allows faster heating and/or improved browning of the food in contact with the ovenware surface. The composition can be formed into ovenware of various sizes and shapes such as pizza, bread, cake and muffin pans. Covers for these vessels may be formed from the same material or other materials if they do not need thermal conductivity and/or to be placed in the oven.