Crush 36 Oreo cookies into fine crumbs using a food processor or rolling pin. Mix with melted butter until resembling wet sand.
Press half the crumb mixture firmly into the bottom of a large trifle bowl to form the base. Set the remaining crumbs aside.
Beat softened cream cheese, powdered sugar, and vanilla extract with an electric mixer until smooth.
Chill heavy cream and whip on medium-high speed until stiff peaks form. Gently fold into the cream cheese mixture.
In a separate bowl, whisk chocolate pudding mix and cold milk for 2 minutes. Let sit for 5 minutes to thicken.
Layer the trifle: Start with the cookie base, followed by half the cream layer, then the chocolate pudding. Add remaining cookie crumbs, and finish with the remaining cream.
Top with crushed Oreos and arrange 6–8 whole Oreos on the surface. Chill for 4 hours before serving.