an accessory is provided for adapting cooking grills , especially grills including a hinged lid , for improved cooking of pizzas and other foods . the accessory includes a body adapted to be disposed between the base and lid portions of the cooking grill , the body being configured to mate with an inner surface of the lid and to cooperate with the base and lid portions to define therebetween a substantially - enclosed cooking chamber when the lid is positioned in a partially - closed position between the open and closed positions . a hinged - lid grill including the accessory is provided also .