In a small saucepan over medium heat, bring ⅔ cup of heavy cream to a simmer. Place 6 oz of semi-sweet chocolate chips in a bowl and pour the hot cream over the chocolate. Let stand for 1 minute, then gently whisk until smooth. Spread the truffle filling over the bottom of the graham cracker crust. Freeze for 20 minutes.

Combine 6 oz of semi-sweet chocolate chips with ½ cup of heavy cream inside of a microwave-safe bowl. Microwave at half power in 30 second increments, stirring in-between each interval. Repeat until fully melted and smooth. Stir in the vanilla and let the chocolate ganache cool to room temperature.

In a chilled bowl, combine the chocolate ganache with 1 cup of heavy cream. Beat until thickened and medium peaks form. Spread the whipped chocolate filling over the truffle filling and refrigerate pie for 6 hours to overnight.

Just before serving, combine 1 cup heavy cream and ¼ cup powdered sugar inside the bowl of an electric mixer. Beat until stiff peaks form. Spread the whipped cream over the top of the pie.

Use a vegetable peeler to peel chocolate shavings directly over the top of the pie. Use a knife to cut the pie into slices. Rinse and wipe the knife with a towel after each cut.