Combine the peanut butter and confectioner's sugar. Sprinkle two third of the mixture in the pie crust. In a saucepan, combine the granulated sugar, cornstarch, and salt. Stir in the milk and the chocolate pieces. Bring mixture to a boil; cook and stir one minute. Add at least half of the mixture to the beaten egg yolks; return to pan. Cook and stir one minute. Add the vanilla. Pour mixture into crust. Cover with plastic wrap and chill. Before serving, spread whipped cream over the pie filling and sprinkle the remaining peanut butter mix.