One of my friends contacted me about a birthday cake for her sister, who used to cover her textbooks with little drawings of puff-esque characters. One such example was Potter Puff.
Originally she wanted to see if I could put Harry's head on the cupcakes, and I suggested we just do a cupcake cake with the whole image. She loved it and the rest is history.
I used Funfetti cupcakes with home-made white icing. I mixed each color from the original white icing, drew the image on the iced cupcakes, then filled in the drawing with the various colors.