Preheat the oven to 375 ° Prepare the pie crust according to recipe directions. Pat into the pan. Line the crust with parchment paper and fill with beans. Bake until edges begin to color, about 15 minutes. Remove paper and weights and continue baking until golden brown.
Cool completely on a wire rack.
In a medium saucepan, whisk together the ⅔ cup sugar, cornstarch, cocoa powder, and salt.
Whisk in the milk, stirring well. Cook over medium-high heat, whisking constantly until mixture begins to thicken, about 5 to 7 minutes.
Whisk in the chocolate chips and 1 teaspoon vanilla until well blended. Allow mixture to cool slightly.
Pour cooled mixture into baked and cooled pie shell. Cool to room temperature and then chill for several hours.
Prior to serving, whip the cream, remaining teaspoon of vanilla, and the powdered sugar in a medium bowl until soft peaks are formed. If you know you are going to consume the pie in the next 24 hours, go ahead and top the pie with the whipped cream. Otherwise, serve the whipped cream alongside the pie.
Notes
Cover leftovers and refrigerate. Leftovers will keep for 3 days.Nutritional values are approximate and based on ⅛ pie.