My eldest child just turned eight. My how time flies! She really wanted to make a cake with me for her birthday. So, she helped to make the cake mix and I did the decorating. We decided a butterfly cake would be fun to make, but I didn't want to spend the money on a shape pan. Instead, I used a loaf pan and cupcakes to make the shape. Here is the process:
After baking, allow to cool and remove from pans. Then, take the loaf pan and trim the corners off to create the body of the butterfly. Keep two of the corners you trimmed. Leave a little flat area on both the top, bottom, and each side.
Ice it on the top and all sides. I used white cream cheese icing. You'll need to "dirty ice" it first, chill for a bit, then add another layer of icing to ensure no crumbs are seen. Ice both of the corners that you kept as well. Ice the cupcakes. I left mine in paper wrappers, but you could remove them.
The loaf you trimmed becomes the body of the butterfly. Center it on whatever pan you want to use. Two cupcakes plus a corner you trimmed become the upper wings on each side. One cupcake becomes the lower wing on each side. Once you have them in place so that they resemble wings, you'll need to place another layer of icing over the top so it covers all of the seams between the pieces. Don't worry about it being perfect since you'll be adding decorative frosting as well.
Decorate the rest of the butterfly with colored frosting. I used the pre-made colored frosting tubes from the grocery store, with the tips that you can purchase for them. You'll have more color options if you mix your own.