Line a 9-inch springform pan with plastic wrap and place it in the freezer.

Preheat oven to 350°F (175°C). Line a baking sheet with parchment paper or heavy-duty aluminum foil.

In a small bowl, combine the crushed cookies and melted butter. Stir until well combined.

Spread the cookie crumb mixture evenly onto the prepared baking sheet. Bake for 7-8 minutes. Let cool completely, then break into bite-sized pieces.

Thaw 1 quart of chocolate ice cream for 15-20 minutes until spreadable. Spread it evenly into the bottom of the prepared springform pan. Freeze for 30 minutes to 1 hour.

Gently warm the hot fudge sauce in the microwave for about 15 seconds until softened. Stir well and spread it over the frozen chocolate ice cream layer.

Sprinkle the prepared cookie crunch pieces evenly over the hot fudge layer. Freeze for another hour.

Thaw the second quart of chocolate ice cream for 15-20 minutes until spreadable. Mix in the chopped chocolate chunks.

Spread the chocolate ice cream and chocolate chunk mixture over the cookie crunch layer. Freeze for at least 4-6 hours, or preferably overnight, until completely firm.

Chill a metal mixing bowl and whisk attachment of a stand mixer (or a regular mixing bowl if using a handheld mixer) in the freezer for at least 30 minutes.

In the chilled bowl, beat the heavy whipping cream, powdered sugar, and clear vanilla flavoring on high speed until stiff peaks form, about 3-4 minutes.

Transfer the whipped cream to a piping bag fitted with a star tip.

Remove the cake from the freezer. Work quickly to decorate, especially in warm weather.

Carefully release the outer ring of the springform pan and remove the plastic wrap.

Place the ice cream cake onto a serving plate or a round disposable cake board. Optionally, use a cake comb to create texture on the sides of the cake.

Hold the piping bag about 0.5 inches above the top edge of the cake. Pipe a shell or swirl pattern around the top edge and repeat around the bottom edge of the cake.

Sprinkle the remaining chocolate chunks and the chopped brownie pieces over the top of the ice cream cake.

Drizzle chocolate syrup over the cake. Return the cake to the freezer until ready to slice and serve.