Abstract: A natural convection steam cooking device with a cooking cavity having a floor defining a lower boundary thereof and a sidewall defining a side boundary thereof, the floor having a plurality of first holes therein, the sidewall having a plurality of second holes therein; a steam chamber disposed below the cooking cavity and along the sidewall, the steam chamber having a pool disposed below the floor; wherein the steam enters the cooking cavity from the steam chamber via both the first holes and the second holes; and wherein the steam circulates within the device in an unforced manner by natural convection. The first holes and the second holes may have a ratio of cross-sectional areas of approximately 2:3. And method(s) of providing steam to, and design of steam flow for, a cooking cavity of a commercial steam cooking device.