Abstract: A proofing cabinet for treatment of dough preparatory to baking in which an upright cabinet having a swingable front door has support brackets on the inside for receiving trays of dough while in the bottom of the cabinet there is detachably inserted an assembly consisting of a lower portion which contains an electrically heated tray for receiving water thereby to supply water vapor to the interior of the cabinet while upstanding from the rear end of the assembly is an electric heater contained within a vertical flue chamber. The vertical flue chamber with the electric heater therein induces circulatory flow of air within the cabinet while maintaining the air at such temperature that condensation of water vapor inside the cabinet walls is inhibited.