In a food processor, combine graham crackers and sugar. Process on high until the crackers become crumbs. Slowly add in melted butter and pulse until graham crackers feel like wet sand. Spread evently in a pie pan -- coating the bottom and sides and using a measuring cup to pack the crackers down. Bake crust at 350˚F for 9 minutes. Set aside to cool.
In a medium sauce pan over medium heat, whisk sugar, cornstarch, salt, milk and egg yolks until combined. Continue whisking until the mixture is *just* about to start boiling. The mixture should start to thicken at this point. Turn off the heat and immediately add chocolate, butter, and vanilla until everything is melted and combined.
Pour pudding over cooled graham cracker crust. Smooth the top with an offset spatula. Place in the refrigerator to chill for at least 4 hours or overnight. Top with a generous amount of whipped cream before serving!