01 - Combine graham cracker or chocolate cookie crumbs with sugar in a medium bowl. Pour in melted butter and stir until evenly moistened. Press mixture firmly into the bottom and up the sides of a 9-inch pie dish. Freeze for 15 minutes to set.
02 - Preheat oven to 350°F. Bake the chilled crust for 10 minutes until lightly golden. Remove from oven and allow to cool completely before filling.
03 - Place chopped chocolate in a heatproof bowl set over a saucepan of barely simmering water, creating a double boiler. Stir frequently until completely smooth. Remove from heat and let cool to room temperature.
04 - In a large bowl, beat unsalted butter and powdered sugar with an electric mixer on medium speed for 2-3 minutes until light and fluffy.
05 - Pour the cooled melted chocolate and vanilla extract into the butter mixture. Beat on medium speed until fully incorporated and smooth.
06 - Add eggs one at a time, beating on medium-high speed for 3-5 minutes after each addition. The mixture should become silky, pale, and significantly increased in volume.
07 - Spread the chocolate filling evenly into the cooled crust, smoothing the top with a spatula. Refrigerate for at least 4 hours or until completely set.
08 - Just before serving, whip cold heavy cream with powdered sugar and vanilla extract using a mixer or whisk until soft peaks form. Spread or pipe over the chilled pie surface.
09 - Garnish with chocolate shavings if desired. Slice pie while cold and serve immediately.