Step 1: Crush 30 chocolate sandwich cookies finely using a food processor or by placing them in a zip-top bag and crushing with a rolling pin.
Step 2: In a medium bowl, combine the crushed cookie crumbs with 6 tablespoons of melted unsalted butter, mixing until thoroughly combined.
Step 3: Press the cookie mixture firmly and evenly into the bottom of a 9-inch springform pan. Refrigerate for at least 15 minutes while preparing the filling.
Step 4: In a large mixing bowl, beat 8 ounces of softened full-fat cream cheese with 1 cup of powdered sugar and 1 teaspoon of vanilla extract until the mixture is smooth and creamy, ensuring there are no lumps.
Step 5: In a separate, chilled large bowl, whip 2 cups of cold heavy whipping cream with an additional 1/2 cup of powdered sugar and 1 teaspoon of vanilla extract until stiff peaks form. Be careful not to over-whip.
Step 6: Gently fold about half of the prepared whipped cream into the cream cheese mixture until just combined, being careful not to deflate the air.
Step 7: Spread the cream cheese mixture evenly over the chilled cookie crust in the springform pan.
Step 8: Carefully spread the remaining whipped cream over the cream cheese layer, smoothing the top with a spatula.
Step 9: Crush the remaining 5 chocolate sandwich cookies coarsely and sprinkle them generously over the top of the cake for garnish.
Step 10: Cover the cake loosely with plastic wrap and refrigerate for a minimum of 6-8 hours, or preferably overnight, to allow it to set completely and for the flavors to meld.