Blind-bake pastry crust and set aside. Melt the 4 tablespoons of chocolate chips in 30 second intervals in the microwave, stirring until melted. Using a pastry brush, paint the bottom of the pie crust with the melted chocolate. Place piecrust in the refrigerator until chocolate has hardened.
Mix together the gelatin and 4 tablespoons of water; set aside.
In a large saucepan, combine the milk, half and half, egg yolks, sugar, and cornstarch. Cook over medium-high heat, stirring constantly until the mixture comes to a boil and thickens. Remove from the heat and add the gelatin mixture, as well as the vanilla. Once mixed, remove 1 1/2 cups of the custard and set aside. To the remaining custard, add the 6 oz of bittersweet chocolate, stirring until the chocolate has melted. Allow both custard mixtures to cool.
Remove the prepared piecrust from the refrigerator and pour the cooled chocolate custard into the piecrust. Return to the refrigerator and allow to chill for 30 minutes. Spread vanilla custard on top of chocolate custard and refrigerate overnight.
Prepare the vanilla whipped cream and spread on chilled pie; sprinkle on chocolate shavings and serve.
Vanilla Whipped Cream
Combine all ingredients in a large bowl and using a mixer, beat all ingredients until stiff peaks form. Use immediately.