Line the bottom of a 9-inch (23cm) springform pan with parchment paper and lightly grease the sides.
Combine the Oreo crumbs and melted butter in a bowl until the crumbs are evenly moistened.
Firmly press the cookie mixture across the bottom and partially up the sides of the springform pan. Refrigerate the crust while preparing the cheesecake filling.
In a large mixing bowl, beat the room-temperature cream cheese, granulated sugar, and vanilla until completely smooth and creamy.
In a separate chilled mixing bowl, combine 1 1/4 cups heavy whipping cream and 3/4 cup powdered sugar. Whip on high speed until stiff peaks form.
Add approximately half of the whipped cream to the cream cheese mixture. Gently fold until mostly incorporated.
Fold in the remaining whipped cream, working gently to preserve as much air as possible.
Add the Oreo crumbs and chopped Oreos. Fold gently until evenly distributed throughout the cheesecake filling.
Spoon the filling into the chilled Oreo crust. Spread it evenly and smooth the surface with an offset spatula or the back of a spoon.
Refrigerate the No Bake Oreo Cheesecake for at least 5–6 hours, preferably overnight, until completely firm.
To prepare the topping, combine 3/4 cup cold heavy whipping cream, 6 tablespoons powdered sugar, and 1/2 teaspoon vanilla extract in a mixing bowl. Whip until stiff peaks form.
Once the cheesecake is fully set, carefully release and remove the springform pan. Transfer the cheesecake to a serving plate.
Pipe whipped cream around the edge of the cheesecake. Decorate with Oreo halves and additional cookie crumbs.
Keep refrigerated until ready to slice and serve.