A cooking appliance includes a cabinet that defines a vertical direction and an inner shell positioned within the cabinet. The inner shell defines a cooking chamber therein. The cooking appliance also includes an upper heating module positioned at or proximate to an upper wall of the inner shell. The cooking appliance further includes a movable platform mounted to the inner shell within the cabinet. The movable platform is configured to move along the vertical direction between a bottom position wherein the movable platform is at least partially flush with a bottom wall of the inner shell and an elevated position wherein the movable platform is positioned above the bottom wall of the inner shell.