For my son's first birthday, I made Cookie Monster cupcakes. I just made a batch of cupcakes from a box mix (any flavor will do). Then, I frosted them white and covered them in blue sprinkles. For the googly eyes, I cut mini marshmallows in half and dotted each eye with a black marker with edible dye. I dabbed frosting on the underside of the eyeballs to help them stick to the cupcake. 

The crowning glory was the mouth. I took small store-bought cookies and shoved them into the cupcakes, so it looked like Cookie was eating a cookie. In some cases, I had to use only half a cookie so they would fit in the cupcake.  They were a big hit with the guests.