Step 1: Prepare a 9-inch springform pan by lining it completely with plastic wrap, leaving an overhang on all sides. Lightly grease the pan sides first to help the plastic wrap adhere smoothly.
Step 2: In a medium bowl, combine the crushed Oreo cookies and melted butter. Mix until well combined. Press this mixture firmly and evenly into the bottom of the prepared springform pan. Place the pan in the freezer for at least 15-20 minutes to allow the crust to set.
Step 3: Remove the chocolate ice cream from the freezer and let it soften at room temperature for 10-15 minutes until it's spreadable but not melted. Spoon about half of the softened chocolate ice cream over the frozen cookie crust. Spread it evenly using an offset spatula or the back of a spoon. Return the pan to the freezer for at least 30-45 minutes, or until the ice cream layer is firm.
Step 4: Once the chocolate ice cream layer is firm, drizzle about half of the hot fudge sauce and half of the caramel sauce evenly over the top. You can create a swirling pattern or simply spread it gently. Return the pan to the freezer for another 15 minutes to allow the sauces to firm up slightly.
Step 5: Repeat Step 3 with the vanilla ice cream. Remove it from the freezer to soften, then spoon about half of the softened vanilla ice cream over the firm fudge and caramel layer. Spread evenly. Freeze for at least 30-45 minutes until firm.
Step 6: Drizzle the remaining hot fudge sauce and caramel sauce over the firm vanilla ice cream layer. Return to the freezer for 15 minutes.
Step 7: If desired, repeat Step 5 with the remaining chocolate ice cream for a third layer. Otherwise, proceed to the next step.
Step 8: Spread the thawed whipped topping evenly over the top of the final ice cream layer. Garnish with extra crushed Oreos, chocolate shavings, or sprinkles if desired. Cover the entire ice cream cake tightly with the overhanging plastic wrap or an additional layer of plastic wrap to prevent freezer burn. Freeze for a minimum of 4-6 hours, or preferably overnight, for best results and firm slicing.
Step 9: When ready to serve, remove the ice cream cake from the freezer and let it sit at room temperature for 10-15 minutes to soften slightly. This will make it easier to cut. Release the springform pan sides and carefully peel away the plastic wrap. Dip a sharp knife in hot water and wipe it clean between each slice for clean cuts. Serve immediately and enjoy your delicious homemade ice cream cake!