Crush 20 Oreo biscuits with cream. Combine with 4 tbsp melted butter. Press down into a tin to set the base. Chill for 30 minutes.
Beat 1 cup cream cheese, ½ cup powdered sugar, and 1 tsp vanilla until creamy. Fold in 1 cup whipped cream for a light and creamy filling.
Crush about 8 more Oreos and fold them gently into the cream cheese filling. Don't overmix—leave chunks for bite.
Spread the filling over the cold base. Evenly smooth the top. Chill for 6–8 hours or overnight until firm.
Sprinkle with 2 tbsp of finely chopped pistachios before serving. Provides crunch and a pop of fresh color contrast to the dark, creamy pie.