Prepare the crust:
In a small bowl, combine the graham cracker crumbs, melted butter, and sugar. Mix until fully combined. Press the mixture into the bottom and up the sides of a small pie dish or tart pan. Refrigerate the crust for about 10 minutes to set.

1. Make the chocolate filling:
   In a medium saucepan, whisk together the milk, heavy cream, cornstarch, and salt. Heat over medium heat until the mixture begins to bubble, stirring constantly to prevent clumps. Once it thickens, remove from the heat.
2. Melt the chocolate:
   Add both the semi-sweet and milk chocolate chips to the hot cream mixture. Stir until the chocolate has fully melted and the filling is smooth. Stir in the vanilla extract.
3. Assemble the pie:
   Pour the chocolate filling into the prepared crust. Smooth the top with a spatula and refrigerate for at least 4 hours, or until fully set.
4. Serve:
   Once the pie has chilled, slice it into two portions. Optionally, top with whipped cream, chocolate shavings, or additional chocolate chips for an extra touch of elegance.