Line a 9-inch springform pan with plastic wrap and set aside.
Preheat the oven to 350°F (175°C). Line a 10×15-inch baking sheet with parchment paper.
In a small bowl, combine the crushed chocolate sandwich cookies and melted butter until evenly coated.
Spread the cookie mixture evenly onto the prepared baking sheet.
Bake for 7–8 minutes.
Remove from the oven and allow the cookie crumbs to cool completely.
While the cookie crumbs cool, remove the chocolate ice cream from the freezer and let it soften for 15–20 minutes.
Spread the softened chocolate ice cream evenly into the bottom of the prepared springform pan.
Freeze for 30 minutes to 1 hour until firm.
Microwave the hot fudge topping for about 20 seconds to soften.
Stir until smooth.
Spread the hot fudge evenly over the chocolate ice cream layer.
Sprinkle the cooled cookie crumbs evenly over the fudge layer.
Return the cake to the freezer for 1 hour.
Remove the vanilla ice cream from the freezer and allow it to soften for 15–20 minutes.
Spread the softened vanilla ice cream evenly over the cookie crumb layer.
Freeze for 4–6 hours or overnight until completely firm.
Make the Frosting
Place your mixing bowl in the freezer for about 30 minutes before preparing the frosting.
Add the heavy cream, powdered sugar, and clear vanilla flavoring to the chilled bowl.
Beat on medium speed until the powdered sugar is incorporated.
Increase to high speed and beat until stiff peaks form, about 3–4 minutes.
Transfer 1 cup of the whipped cream frosting to a piping bag fitted with a large star tip.
Assemble and Decorate
Remove the ice cream cake from the freezer.
Remove the outer ring of the springform pan.
Carefully transfer the cake to a serving platter or cake board.
Quickly frost the top and sides with the remaining whipped cream frosting.
Pipe decorative borders or swirls around the top edge of the cake.
Sprinkle the top with colorful sprinkles.
Return the cake to the freezer until ready to serve.