Here is the book cake that I decorated for the girl whose book invitations I made a few weeks ago (scroll down to see photos of the invitations). It was lemon cake with vanilla buttercream. I carved a 9x13 sheet cake to look like an open book, then frosted it and covered it with fondant for the "pages." I used edible food markers to write the words. The "bookmark" is also made of fondant. To finish off the cake, I piped the sides with white frosting (using a serrated tip) and then added a blue border around the edges. I was really happy with how it turned out, especially since it was the first book cake I've ever done!