Heat your oven to 300°F and lightly grease a 9-inch springform pan or pie dish. Crush the chocolate cookies into fine, uniform crumbs—you want them almost like sand, not chunky pieces. Melt 7 tablespoons of butter and stir it into the cookie crumbs until the mixture resembles wet sand and holds together when pressed. Press this mixture firmly and evenly into the bottom of your prepared pan, creating an even layer about 1/4-inch thick. Freeze for 10 minutes to set the base, then bake at 300°F for 10 minutes to stabilize it. Remove from oven and set aside to cool slightly while you prepare the filling.

Increase oven temperature to 350°F. In a heatproof bowl set over simmering water (or using a double boiler), melt 6.5 oz of chocolate with 1/4 cup butter, stirring until completely smooth and glossy. Remove from heat and stir in 1/3 cup whiskey, 1 tbsp cocoa powder, 1.5 tbsp vanilla, and a pinch of salt until fully incorporated. Set this chocolate mixture aside to cool slightly while you prepare the eggs.

Separate your room-temperature eggs. In a medium bowl, beat the 6 egg yolks with 1/2 cup brown sugar for about 5 minutes until the mixture is pale, thick, and ribbons form when you lift the beaters—this incorporates air that will create lift in the pie. Fold this yolk mixture into the chocolate mixture from Step 2 until no streaks remain. In a separate, very clean bowl, beat the 6 egg whites with 1/2 cup sugar until soft peaks form (the peaks should curl slightly when the beaters are lifted). I like to use an electric mixer for this step to ensure maximum volume. Gently fold the egg white mixture into the chocolate mixture in two additions, being careful not to deflate the whites—use a rubber spatula and fold from the bottom up.

Pour the chocolate-egg mixture into the cooled crust from Step 1, smoothing the top gently. Bake at 350°F for 35-40 minutes until the top is set but the center still has a slight jiggle when you gently shake the pan—this ensures a moist, fudgy texture rather than a dry cake. Remove from the oven and let cool to room temperature, about 1 hour, then refrigerate while you prepare the coffee pudding layer.

In a medium saucepan, combine 3/4 cup sugar, 1/3 cup cocoa powder, 1/3 cup cornstarch, 3 tbsp espresso powder, and 1/4 tsp salt. Whisk these dry ingredients together to break up any lumps. In a separate bowl, whisk together 4 egg yolks and 2.5 cups milk until smooth. Pour the milk mixture into the dry ingredients and whisk until completely smooth with no lumps. Place the pot over medium heat and stir constantly. Once it reaches a boil, continue stirring for exactly 30 seconds—this ensures the cornstarch fully sets. Remove from heat and immediately stir in 3 tbsp butter, 3.5 oz finely chopped chocolate, and 2 tsp vanilla until smooth and glossy. Pour the pudding into a shallow dish and press plastic wrap directly onto the surface to prevent a skin from forming. Refrigerate for at least 3 hours, or until well-chilled and set—I often make this the day before for convenience.

Spread the chilled pudding from Step 5 evenly over the cooled chocolate cake from Step 4. In a heatproof bowl set over simmering water, melt 7 oz chocolate with 1 cup cream, stirring until completely smooth. Remove from heat and let cool to room temperature, about 10 minutes, then stir in 2.5 tbsp powdered sugar and 2.5 tbsp Irish cream. In a separate bowl, beat 1 cup of well-chilled cream to soft peaks, then gently fold it into the chocolate mixture until no white streaks remain. Spread this chocolate mousse evenly over the pudding layer. Finally, beat the remaining 1 cup well-chilled cream with 2.5 tbsp powdered sugar and 2.5 tbsp Irish cream until stiff peaks form. Spread or pipe this whipped cream over the mousse, creating peaks for visual appeal. Top with shavings or pieces of chocolate if desired.

Refrigerate the assembled pie for at least 2 hours (or overnight) to let all the layers set and flavors meld together. This resting time is crucial—the pie actually tastes better the next day as the whiskey, coffee, and Irish cream flavors develop more depth. Slice with a warm, wet knife, wiping between cuts for clean slices. Serve chilled and enjoy!