An outdoor cooking oven comprises a reconfigurable heat deflector system and independently-controllable air vents that enable the cooking oven to be configured for various cooking methods, such as low and slow cooking or grilling. At least first and second shelves are mounted within a cooking chamber with the second shelf positioned beneath the first shelf. A heat deflector system disposed on the second shelf comprises at least first and second heat deflector elements that are removable from the cooking chamber to enable a user to reconfigure the heat deflector system to vary indirect heating of food items disposed on the first shelf. At least first and second air vents disposed in a bottom side of the exterior encasement beneath the cooking chamber are independently controllable to allow at least first and second airflows from the vents to be independent varied.