Line a 9-inch springform pan with plastic wrap. Place in the freezer.
Preheat the oven to 350°F. Line a baking sheet with parchment paper or heavy-duty aluminum foil.
In a small bowl, combine the crushed cookies and melted butter. Stir to combine.
12 chocolate sandwich cookies chocolate creme filled
Spread the cookie crumb mixture on the lined baking sheet. Bake for 7-8 minutes. Cool completely, then break into bite-sized pieces.
Thaw 1 quart of chocolate ice cream for 15-20 minutes. Spread evenly into the bottom of the prepared springform pan. Freeze for 30 minutes to 1 hour.
12 chocolate sandwich cookies chocolate creme filled
Microwave the hot fudge sauce for 15 seconds to soften. Stir well, then spread evenly over the chocolate ice cream layer.
12 chocolate sandwich cookies chocolate creme filled
Sprinkle the cookie crunch pieces over the hot fudge layer and freeze for 1 hour.
12 chocolate sandwich cookies chocolate creme filled
Thaw the second quart of chocolate ice cream for 15-20 minutes. Mix in 1 cup of the chocolate chunks.
12 chocolate sandwich cookies chocolate creme filled
Spread the second ice cream layer over the cookie crunch layer. Freeze for 4-6 hours, or preferably overnight.
Chill a metal mixing bowl of a stand mixer (or a regular mixing bowl if using a handheld mixer) for 30 minutes.
In the chilled bowl, beat the heavy cream, powdered sugar, and clear vanilla flavoring on high speed until stiff peaks form, about 3-4 minutes.
12 chocolate sandwich cookies chocolate creme filled
Fill a disposable piping bag fitted with a star-shaped tip with the whipped cream.
Remove the cake from the freezer. Work quickly, especially if the weather is warm.
Release the outer ring of the springform pan and carefully remove the plastic wrap.
Place the ice cream cake on a serving plate or a round disposable cake board. (Optional: Use a cake comb to create texture on the outside of the cake).
Hold the piping bag about 0.5 inches above the edge of the top of the cake. Use steady, even pressure to pipe a shell or swirl pattern around the top edge of the ice cream cake. Repeat for the bottom edge of the cake.
Sprinkle the remaining chocolate chunks and the chopped brownie pieces on the top of the ice cream cake.
12 chocolate sandwich cookies chocolate creme filled
Drizzle chocolate syrup over the ice cream cake. Place the cake back into the freezer until ready to slice and serve.
12 chocolate sandwich cookies chocolate creme filled