We used boxed cake mixes to save time for our Butterfly First Birthday Cake. (Found from experience that if you mix it for about 5 minutes it comes out so much better). The bottom layer is chocolate with chocolate frosting on top, then a strawberry layer with strawberry frosting on top, then a white layer with cream cheese frosting over the whole cake. Then we used white fondant to cover the cakes.
Then we used colored fondant to create the butterflies, ladybugs, and caterpillar. The banner is fondant and written on with frosting dye. I cooked the cakes and my 14 year old daughter made and placed the decorations on the top.