In a large bowl or stand mixer fitted with a whisk attachment, whisk together the frosting ingredients until thick and fluffy.
Spread the frosting over the top of the cake.
TOPPING:
Add the Oreos to a food processor and pulse until fine crumbs form. Sprinkle the Oreo crumbs over the top of the cake.
Write R.I.P. on the Milano cookies to make tombstones and then press them into the frosting so they stand up.
Press the ghost Peeps into the frosting so they stand up. If they have a hard time doing so, you can use toothpicks to help secure them.
Add the candy pumpkins near the ghosts and tombstones.
Add sprinkles, if desired.
ENJOY!
