Step 1: Prepare cake mix according to package directions. Divide batter evenly between two greased and floured 8-inch round cake pans. Bake as directed until a toothpick inserted into the center comes out clean.
Step 2: Let cake layers cool in pans for 10 minutes, then invert onto a wire rack to cool completely. This is crucial for the stability of your ice cream cake recipe.
Step 3: Line the bottom of an 8-inch springform pan with parchment paper. Place one cooled cake layer at the bottom of the prepared springform pan.
Step 4: Spread half of the slightly softened vanilla ice cream evenly over the first cake layer. Use an offset spatula or the back of a spoon to smooth it out.
Step 5: Drizzle generously with half of the cooled hot fudge sauce. If using, sprinkle with half of the crushed chocolate sandwich cookies.
Step 6: Place the springform pan in the freezer for at least 30 minutes, or until the ice cream layer is firm. This ensures a stable foundation for your ice cream cake recipe.
Step 7: Once the first ice cream layer is firm, carefully place the second cooled cake layer on top.
Step 8: Spread the remaining softened vanilla ice cream evenly over the second cake layer.
Step 9: Drizzle with the remaining hot fudge sauce and sprinkle with the remaining crushed cookies (if using). Smooth the top of the ice cream as much as possible.
Step 10: Cover the springform pan tightly with plastic wrap and freeze for at least 6-8 hours, or preferably overnight, until the ice cream cake recipe is completely firm.
Step 11: To serve, remove the springform pan. Run a thin knife around the edge of the cake to loosen it, then release the springform clasp and carefully remove the sides. Transfer the ice cream cake to a serving plate.
Step 12: Decorate with whipped cream or frosting and sprinkles as desired. For clean slices, dip a sharp knife in hot water and wipe it clean before each cut. Serve immediately and enjoy your homemade ice cream cake recipe!