For some reason, there is a slight ripple or bulge in my cakes where the layers meet. It is driving me crazy! Everything is completely smooth when I ice the cake and lay the fondant on. It's after a while that I notice it isn't perfectly flat on the sides. It shows up in pictures so I know I am not being a perfectionist. No one has seemed to notice or care but I know it could and should look better.
Any ideas why this is happening?
Are you giving your cakes time to settle after stacking and filling and before icing, or at least pressing down well on the top before icing? Sounds like the cake is settling after it's been iced, and pushing filling out between the layers, causing a bulge.
Whenever possible I fill and crumb coat my cakes, then let them sit a few hours or overnight before icing them, so that whatever settling they're going to do is done before the final coat of icing.
It sounds like the filling between your layers is either too soft or too thick. The weight of the top layer starts pressing down and it just bulges out after a while.
It could definitely be the filing layer is too thick. I have always waited until the crumb coat is cold and then iced. I will definitely give it more time to settle this time around.
Just out of curiosity - how thick a layer of filling should I be using?
Silveryriver, I agree with magda and costume czar. It sounds like your layers have not had time to settle before you put your fondant on. You could try putting some books on top to help force the settling before crumbcoating. Another trick you could try is actually put a final layer of ganache on before putting on your fondant this helps with bulging.
My cakes (4" high) have normally 4 layers. One layer is about 3/4" cake and 1/4" buttercream.