8 Tbs unsalted butter
2 cups finely crushed chocolate wafer cookies (about 5 oz.)
2 Tbs Cognac
5 oz. bittersweet chocolate, finely chopped
4 large egg yolks
2/3 cup plus 2 tablespoons dark brown sugar
1 Tbs cornstarch
1/8 tsp salt
2 cups plus 2 Tbs heavy cream
1 cup plus 2 Tbs whole milk
1 1/2 tsp pure vanilla extract
1 Tbs cocoa powder
1. Make the crust: Preheat oven to 350°F. Melt 4 tablespoons of butter. Stir the crushed cookie crumbs, melted butter, and Cognac in a medium-size bowl. Press the crumb mixture into the bottom and all around the sides of a pie pan. Bake for 10 minutes, remove from oven, and cool completely on a wire rack.
2. Make the pudding: Place the chocolate in a large bowl and set aside. Whisk the egg yolks, 2/3 cup brown sugar, cornstarch, and salt in a medium bowl and set aside. Heat 1/2 cup plus 2 tablespoons cream, milk, and remaining butter in a medium saucepan over medium-high heat until the mixture just begins to boil. Remove from heat and, whisking continuously, gradually add the hot milk to the egg mixture. Return the milk-and-egg mixture to the saucepan and, whisking continuously, cook over medium heat until mixture comes to a boil. Cook for 1 more minute, whisking continuously, and stir in 1 teaspoon vanilla extract. Remove from heat and strain the pudding into the bowl with the chocolate. Let sit for 2 minutes and fold the chocolate into the pudding with a spatula. Cool to room temperature.
3. Finish the pie: Pour Caramel Sauce into the bottom of the pie crust and refrigerate for 10 minutes. Spread the pudding over the caramel and chill for 2 hours. Beat the remaining cream, brown sugar, vanilla, and the cocoa powder in a large bowl until stiff peaks form. Top the pudding with the cream and chill for 30 minutes or up to 6 hours.