In a pie dish combine cookie crumbs and melted butter. Mix until all crumbs are covered with butter. Press the crust onto the bottom and the sides of the pan. Leave it in the freezer while preparing the filling.
Prepare the pudding according to the package instructions, with 4 tbs sugar and 450 ml milk instead of 500. Let it cool almost until room temperature whisking from time to time (this is not necessary if you are preparing an instant pudding as it will not be hot). Pour the pudding into the pan, on top of the crust. Spread some broken cookies and chocolate on top.
Using an electric mixer whip the cream until very thick. With a rubber spatula gradually fold in the melted white chocolate. Mix gently until smooth.
Spread the topping on top of the filling. Cover the pan with cling film and let it stay in the fridge for 4-6 hours before serving.