Preheat the oven to 375 degrees F.
For the crust, use a food processor to pulse the peanut butter cookies until they are finely ground. (You need to have 1-1/2 cups). Mix in the sugar, butter and salt.
Press the cookie crumbs into the bottom and up the sides of a 9-inch pie dish. Freeze for 15 minutes. Bake until golden and toasted, about 12 minutes. Cool completely on a wire rack.
For the pudding, whisk together the sugar, cornstarch, salt, egg yolks and milk in a large saucepan over medium-high heat. Continue whisking constantly and bring the mixture to a boil. Keep whisking for 2 minutes until it has thickened. Remove from the heat and stir in both chocolates until they have melted followed by the butter. Whisk in the peanut butter powder.
Pour the filling into the crust smoothing into an even layer. Let the pie stand at room temperature for 30 minutes. Chill in the refrigerator for 1hour before covering with plastic wrap, pressing directly onto the pudding. Chill until set, at least 2 hours up to 2 days.
For the whipped cream, use an electric mixer to beat the heavy cream, confectioners’ sugar and vanilla to medium peaks. Spread the whipped cream on top of the pudding.
Serve immediately. Store leftovers covered in the refrigerator.