Combine rice flour, corn flour, and water in a medium non-stick saucepan over medium heat. Stir as it comes to a gentle boil. The mixture will begin to thicken to a paste like consistency. This will take about 5 minutes. Turn off stove.
Prepare a steamer. Transfer rice and corn flour paste to a greased bowl or tray. Place the bowl or tray in the steamer and allow it to steam for 1 hour. Top up water in steamer if necessary.
Remove and allow rice cake to cool completely. Refrigerate overnight.