Finely crush chocolate wafers or Oreos. Use a food processor blender if possible. Combine chocolate wafer crumbs and melted butter in small bowl. Press in the bottom and up the sides of a 8-9 inch pie plate to form crust.

Using a nonaluminum saucepan heat together the milk and chocolate over low heat. Whisk until the chocolate is melted, it will look speckled.

In a large bowl, whisk together the egg yolks and sugar until pale yellow. Add the cornstarch and salt, then the vanilla, and whisk until well blended. Slowly pour the warm chocolate mixture into the yolk mixture, whisking constantly until well blended. Return the mixture to the saucepan and cook over medium heat until it thickens and begins to bubble slowly, 6 to 8 minutes. Remove from the heat and stir until smooth, about 1 minute.

Pour the filling into the crumb crust and smooth with a spatula. Cover with plastic wrap, pressing it directly onto the surface, and refrigerate until completely cold and firm, 2 to 3 hours.

With an electric mixer whisk together the cream, sugar and vanilla on medium-high speed until stiff peaks form. Spread the whipped cream on the chilled pie. Decorate with chocolate curls. Refrigerate until ready to serve. Allow to the pie stand at room temperature for 20 minutes before serving to for easier cutting.