Both. If the cake I am working on is 6", 8" and 10" I glue two cardboard cake boards togeter for the 6" and 8". For the 10" I glue one cardboard cake board to the cake drum I am using as the main base. I never glue more than 1 cardboard cake board to the cake drum for the bottom tier. There is no point in that.
5/11/11 at 5:50am