Make the crust: Crush 300 g Oreo cookies into fine crumbs. Mix with melted butter and press firmly into the bottom of a 23 cm springform pan. Chill in the fridge for 20 minutes.
Prepare filling: Beat cream cheese with powdered sugar and vanilla until smooth and creamy.
Whip cream: In a separate bowl, whip cold heavy cream to stiff peaks. Gently fold into the cream cheese mixture.
Add Oreos: Stir in chopped Oreo pieces until evenly distributed.
Assemble: Spread the filling evenly over the chilled crust. Smooth the top with a spatula.
Chill: Refrigerate for at least 6 hours or overnight until firm.
Decorate & serve: Top with extra Oreo cookies before slicing.