My son wanted Optimus Prime and Bumblebee on his 4th birthday cake. I found a wonderful marshmallow fondant recipe – very easy and very easy to work with. Used gel coloring for the fondant.
I made Bumblebee out of 2 9in rounds; Optimus out of a 13×9 pan. I used butter cream icing under the fondant. I made the cakes last night, cut them into the block shape and froze them, they were easier to carve out.
I think this Transformers birthday cake turned out pretty great!