Abstract: A divider for an oven includes a first panel configured to spatially separate the oven cavity into respective upper and lower sub-cavities. The first panel defines a first plurality of apertures therethrough. A second panel is slidably mounted to the first panel and defines a second plurality of apertures that are collectively moveable relative to the first plurality of apertures by sliding of the second panel relative to the first panel between a heat transmission position and a closed position, wherein the ones of the second plurality of apertures are respectively aligned and unaligned with the respective ones of the first apertures. In various aspects, the divider may be configured as an integrated or permanently installed feature of an oven or may be a removable accessory for use with an oven.