Allow the ice cream to soften to room temperature, about 10 minutes.
Place your Oreos in a food processor and pulverize until it resembles a fine sand texture.
Combine the butter with the oreo crumble until well combined. It will be very soft and moldable.
Pour the Oreo butter crust mixture into a 9 inch springform pan that has been lined with parchment.
Place your Kit Kat bars individually around the outside of the pan, Kit Kat symbol outward. Press them down into the Oreo crust, this will hold them in place.
Place it into the freezer for 10 minutes to harden slightly.
Remove the crust from the freezer and pour your softened chocolate Kit Kat ice cream over the crust. Place it back into your freezer for at least 2 hours to refreeze.
Cover the top with a layer of room temperature chocolate fudge sauce.
Cover chocolate with chopped Kit Kat pieces.
Add softened (vanilla) Kit Kat ice cream layer on top of chopped Kit Kats.
Refreeze for at least 2 hours.
Add some more chocolate fudge sauce to top of cake and then enough M&M's to completely cover it. Sometimes I just add M&M’s to cover the top but the M&M's stay in place better if using chocolate sauce.
Refreeze cake until needed. Ideally for 6 hours to overnight, if possible. You want to be able to get the best slices when serving.
Run sharp knife under hot water to make slicing easier. Slice and serve.