In a mixing bowl, combine graham cracker crumbs, melted butter, and sugar. Mix until evenly moistened.
Press the mixture firmly into the bottom and sides of a 9-inch pie dish to form the crust. Chill while preparing the filling.
In another bowl, whip the heavy cream until stiff peaks form. Set aside.
In a separate bowl, beat cream cheese until smooth. Add powdered sugar and sifted cocoa powder. Mix until creamy.
Gently fold the whipped cream into the chocolate cream cheese mixture until well combined.
Pour the filling into the chilled crust and smooth the top with a spatula.
Cover and refrigerate for at least 4 hours or overnight until firm.
Garnish with chocolate shavings, whipped cream, or berries before serving (optional).