My niece, Brookelyn, like so many other little girls are into Princesses. Her mom asked me to make a princess castle. This is Wilton's Princess Castle Cake Set. Just followed their instructions. http://www.wilton.com/idea/The-Princess-Address. I had never used Royal icing before, it was interesting. The purple on the tops of the towers is just royal icing. It makes for easy cleaning, it shatters like glass if you drop it (so we found out).