Mocha Cream Pie

Prepare the cake: Preheat the oven to 350ºF. Put the cookies and salt in a food processor and beat until the cookies are smooth. Pour in the melted butter and beat until the crumbs are moistened. Transfer to a 9-inch-diameter pie dish and sprinkle crumbs evenly over the bottom and top sides to form a crust. Bake for about 15 minutes, until the cake is firm. Allow to cool on a wire rack.Prepare the filling: In a small cup, combine the vanilla and espresso powder until the coffee is dissolved. Combine 1 cup of butter in half with both chocolates in a saucepan and place on the stove over medium-low heat. Cook, whisking frequently, until the chocolate is melted and the mixture is hot, about 5 minutes (it may seem grainy). In a large bowl, whisk together the sugar, cornstarch, and salt. Pour the remaining half cup into the sugar mixture and beat until no lumps remain. Whisk together the egg yolks.While constantly whisking the cornstarch mixture, slowly pour in the hot chocolate mixture. When both mixtures are combined, pour back into the saucepan, place on the stove over medium-low heat and cook, whisking constantly, until they thicken and begin to boil, 5-7 minutes. Pour the hot pudding into a clean medium bowl and toss with the butter and remaining vanilla and coffee mixture. Cover with plastic wrap, pressing the plastic directly against the surface. Let the pudding cool at room temperature for 1 hour, then pour into a pie dish, cover with fresh plastic wrap, and refrigerate for at least 3 hours.Prepare the filling: Half an hour before serving, pour the heavy cream and powdered sugar into a chilled bowl and beat with an electric mixer on medium-high speed until firm peaks form. Remove the foil from the cake and spread the whipped cream on top. Refrigerate for 30 minutes, then slice and serve.