I'm in the pro-Cake Bible camp, but I'm embarassed to say I've never been able to figure out Beranbaum's formula for increasing cake size. My impression is that everything increases proportionally except the baking powder, but - it's an impression. Could someone please take pity on me and help me out with increasing her buttermilk country cake from 9" to 12"? The 9" calls for a tablespoon of baking powder. Assuming everything else is proportional, how much should I use?
Thanks very much in advance.