Preheat oven to 350°.
Place the cookies in a food processor with a standard blade.
Pulse and mix for about 30 seconds until you have "sandy" crumbs.
Remove ½ cup of cookie crumbs to use for the top of the cake. Reserve for later.
To the rest of the crumbs, add the butter and pulse until the crust comes together and folds over on itself. You'll even hear the food processor get a little quieter when it's ready.
Pour the cookie and butter crumb mixture into a 9" x 13" pan. If you have a straight sided pan it makes for a prettier cake, but no worries if you don't!
Bake the crust for 10 minutes and not a minute more. Let cool completely.
Place chocolate chips in a heatproof glass bowl.
Heat 1 cup of the whipping cream in a small saucepan over medium heat until you get small bubbles on the edge of the pan and a slight skim on top of the cream.
Pour heated cream over chocolate chips and whip with a whisk until you get a smooth, creamy ganache.
Pour ganache (or store-bought topping) over cooled crust and evenly spread out with a spatula over the whole crust.
Remove the ice cream from the freezer and using scissors, cut away the outside sides of the packaging, leaving the bottom intact.
Using a sharp knife, cut 6 (approximately 1 ½" thick) slices. Picture you're slicing a loaf of bread so you're cutting from the short side.
Lay slices (two across) down the length of the pan.
Add the remaining 2 cups of heavy whipping cream in a stand mixer or mixing bowl along with the confectioner's sugar and vanilla. Beat on high for 2 minutes until stiff peaks form.
Spread whipping cream (or whipped topping if using store-bought) over the ice-cream layer.
Sprinkle with remaining cookies crumbs.
Freeze for at least 4 hours (or overnight) until firm.
Slice into squares with a sharp knife dipped in warm water between cuts. Remove with spatula and serve.