I recently made a Hello Kitty Bday cake for a coworker and used a Yellow cake recipe as my cake of choice. I used the following recipe http://cakecentral.com/recipe/yellow-cake-3 and the cake came out amazing in taste and I got several compliments. Though I was still a lil concerned because when stacking my cake I noticed it had quite a few air bubble holes in the cake layers. How can I prevent this from happening next time ? Or what could I have dont differently ?