Fully line an 8-inch cake pan with plastic wrap. Place the pan in the freezer for 15 minutes. While the pan chills, place your cartons of ice cream on the counter for 15 minutes to slightly soften.

Use an ice cream scoop to transfer all the ice cream to your lined cake pan. Cover with another layer of plastic then press down into a flat layer. Return the pan to the freeze until the ice cream is very firm again, at least 2 hours. (You can do this stage several days in advance if you’d like! This is also a great time to bake and cool your cake layer.)

Once the ice cream layer is very hard, place the cake layer on a serving plate or cardboard round. Cover the top with the fudge sauce then sprinkle the chopped cookies on top.

Remove the ice cream layer from the freezer. Remove and discard the top layer of plastic wrap. Use the excess from lining the pan to lift the ice cream layer out of the pan. Place it top-side down on top of the cookies and fudge on the chocolate cake. Press the plastic wrap down around the side of the cake, and place in the freezer for at least 1 hour. (You can keep this in the freeze for several days. Tightly wrap it with more plastic wrap or foil, if you do.)

To a large bowl with an electric mixer or to the bowl of your stand mixer fitted with a whisk attachment, combine cold whipping cream, sugar and vanilla. Start mixing with the mixer on low, gradually increasing the speed to high and mix until very soft peaks form, about 3 minutes. Whisk the rest by hand until the peaks firm up, being sure not to over-whip the cream as it will curdle.

Reserve 1 cup of the whipped cream and place it in a piping bag fitted with a large closed star tip (Ateco 846). Place it in the fridge.

Remove cake from freezer and cover with the remaining whipped cream, smoothing the top and sides. Press crumbled cookies onto the bottom edge. If you want to add a fudge drip, freeze the cake for 1 hour before adding it.

To pipe a drip of chocolate onto the edge of the cake, warm additional fudge and place it in a piping bag. Pip it around the top edge of the cake, letting some drip down the sides. Using the reserved whipped cream, pipe a scalloped pattern onto the top edge. Add sprinkles or cherries on top if desired.

You can serve the cake immediately or store the cake in the freezer until ready to slice. If storing for more than a few hours, let it freeze for about an hour to firm up the decorations, then cover it with plastic wrap. Before serving, remove the cake from the freezer and leave it on the counter for about 15 minutes for easier slicing.