Preheat oven to 350 degrees. Line a cookie sheet with parchment paper or a silicone baking mat and set aside.

Combine the Oreo crumbs and melted butter and stir until well combined. Spread the crumbs evenly onto the prepared cookie sheet.

Bake for 8-10 minutes, then allow to cool. Use your fingers to break any big clumps into smaller ones. Set aside.

Line an 8×3 inch cake pan with clear wrap that covers the bottom and goes above the sides of the cake pan.

Set the chocolate ice cream out to soften for about 20 minutes. Stir until smooth and creamy. Add to the prepared cake pan and spread into an even layer. Freeze for 30 minutes.

To make the fudge layer, add the chocolate chips, corn syrup, and vanilla extract to a medium bowl. Heat the heavy whipping cream just until it begins to boil, then pour it over the chocolate chips. Allow to sit for 2-3 minutes, then whisk until smooth.

Remove the cake pan with the chocolate ice cream from the freezer and pour the chocolate fudge over the ice cream, spreading it into an even layer. Freeze for about 10 minutes.

Add the cookie crumbles to the top of the fudge layer, then freeze for about 2 hours, until mostly firm.

Set the vanilla ice cream out to soften for about 20 minutes. Stir until smooth and creamy. Add to the top of the cake, then freeze until firm, for about 2-3 hours.

Use the clear wrap to lift the frozen cake out of the pan and place it on a cardboard cake circle or serving plate. Set it back in the freezer.

To make the whipped cream topping, add the heavy whipping cream, powdered sugar, and vanilla extract to a large mixer bowl. Whip on high speed until stiff peaks form.

Frost the cake with the whipped cream and decorate as desired.

Freeze the cake until ready to serve. Best when stored well covered for 4-5 days.