Set the oven to 350 degrees
Mix the cake mix, egg and butter together - the dough will be crumbly, yet it'll work.
Form the dough into one inch balls, then press them out like large silver dollars.
Bake for 7-9 minutes.
Let the cookies cool for at least 15 minutes.
Take the icing and fill a plastic bag with it and then cut off the end.
Once the cookies are cool, ice one and top it with another cookie.
Stack and eat!