You can buy specialty cake pans in just about every shape you can imagine. But if you want a truly unique form, a knife will be your best friend. With a serrated knife, you can cut cake layers any way you want. Is it messy? You bet. But it also leaves you free to create on a grand scale. With an understructure to add support, a talented carver can go big and bold with sponge cake and buttercream.
Start with sheet-cake pans that will give you layers the size and shape you want to work with. Fill and chill the stacked layers, and then cut the cake into the shape you want, like a Christmas tree, freight train or elephant, with a serrated knife. Cover what's left with fondant or frosting.