Preheat oven to 350°F and line a baking sheet with parchment paper
In a large bowl combine cake mix, eggs, and oil until well combined - mixture will be thick
Scoop batter onto baking sheet and bake 7-8 minutes
Cool 5 minutes on sheet before moving to rack
Start the ganache in a saucepan over medium heat. Whisk butter, cocoa powder, and milk until butter is melted and smooth
Remove from heat and whisk in powdered sugar until smooth
Spoon frosting on top of each cookie
Serve and enjoy!
Notes
Store cookies in an airtight container at room temperature in a dry cool place.This recipe makes large cookies, feel free to use smaller scoops for bite sized sheet cake cookies if you would rather have more to share.