In a saucepan mix together sugar, cornstarch, and salt. Stir in the milk and bring to a boil over low heat. Cook until thickened, stir in the vanilla, butter and peanut butter.
Let cool slightly, mix together on high speed in blender or with a plastic blade in a food processor. Pour into pie shells. Chill well. To serve, top with fresh whipped Cream.
Makes two pies.