It is card stock, we change out the pattern every year.
I went online to find a better detailed instructions rather than trying to explain it in words 
This is identical to what I make but due to food allergies I make this Gluten/Dairy free.
http://www.bettycrocker.com/recipes/easter-bunny-cake/b8af0f55-67d5-4fb0-aaec-ab11ff5df7e3
*Edited to add, I just read through the instructions for that site. This is the SIMPLEST cake to decorate and make! I do not bother with toothpicks, you won't need them, I just attach tail with more frosting. I use licorice for whiskers because I think they are cute and instead of jelly beans I use coated almonds because I think they look better. This is a great tradition to start with your kids, I have such fond memories of this cake!
Edited by Frogdogtimestwo - 4/5/12 at 11:38am