Filling: Mix all ingredients well. Cook over medium heat in a 3 qt. saucepan until thick. Pour into baked pie shell. Cover filling with wax paper. Cool for 30 minutes on counter then put in fridge til chilled.
Topping: You need a good mixer for the whipped cream topping. Put the metal bowl, beater, and the measured out heavy cream into the freezer for 1 hour. When pie is completely chilled, take them out and make the cream topping. Put cream into cold metal bowl and beat on high until it is good a stiff. Add the powdered sugar when it is about half stiffened. Spread the topping onto the chilled pie and garnish with shaved chocolate. Use a cheese grater or a potato peeler to get the desired effect.