Soo it's a cool baking project. Really easy and looks very nice :)
You need your favourite muffin (I did it with coffe muffin :)) and some cream or whipped cream.
Just cut out a piece of the muffin's top, cut it two parts. Take the cream to the cut section's place, and take here the two part - those will be the butterfly's wing.
(Sorry cos the bad English :(()