A commerical, dual tier pizza cooking oven is formed from substantially similar but relatively inverted lower and upper modules. The lower module has a housing, with a cooking chamber therein, which is floor supported in an elevated position by suitable depending support legs and has a downwardly projecting fan and heating section used to create a recirculating flow of air, heated to a suitable food cooking temperature, through the housing. The upper module housing is stacked on top of the lower module housing, and its fan and heating section projects upwardly therefrom and also operates to create a recirculating flow of heated air through its cooking chamber. Perforated metal food support plates are horizontally disposed in each of the two cooking chambers for support the pizzas to be cooked. Plenum structures on opposite sides of the support plates in each of the two cooking chambers operate to receive portions of the heated air recirculated therethrough and convert them to series of heated air cooking jets which evenly blanket the opposite sides of the support plates in a manner transferring heat thereto at an accelerated rate to thereby rapidly and evenly cook the pizzas or other food items supported on the plates.