Take your first layer of ice cream out of the freezer (choc or vanilla, whichever you want to be on the top of the cake when you flip it over) and let it sit at room temp for about 20-30 minutes to thaw.
Line a loaf pan with plastic wrap, with enough room that you can wrap up the top in the freezer.
Mix it up until it's a workable consistency, I transferred to a mixing bowl to make this easier and faster.
Spread the ice cream into the lined loaf pan and spread out until it's even. Tap the loaf pan firmly on the counter a couple times and it should settle well into the corners. Pop in the freezer for about 30 minutes to firm up.
Once the first layer is firmed up, add the cooled chocolate ganache and spread evenly over the ice cream layer.
Sprinkle the cookie crumble on top, spreading evenly as well. Pop back in the freezer for 30 minutes, and pull out your second pint of ice cream to soften for the final layer.
Spread the final layer of ice cream on top of the cookie crumble, then cover with a layer of parchment paper (this will make it easier for cutting and then putting back in the freezer), and then wrap the edges of the plastic wrap over top.
Freeze overnight to firm up.
You can frost the cake with dairy-free whipping cream and decorate with sprinkles and gel icing for the full experience, but I didn't do that.
To serve, flip onto a cutting board, and cut with a knife, wiping the blade between slices. Enjoy!