Cream the peanut butter, cream cheese, and ½ cup of the confectioners sugar together in a large bowl with an electric mixer.
Wash and dry the beaters. Using a chilled medium sized bowl and chilled beaters beat the heavy cream with the mixer until it holds soft peaks.
Blend in vanilla. Add the remaining ½ cup confectioners sugar and continue to beat until stiff but not grainy.
Add about one-third of the whipped cream to the peanut butter mixture. Blend with a mixer until smooth and creamy.
Fold in the remaining whipped cream until the filling is smooth and evenly mixed.
Spoon the filling into the chilled pie shell and smooth the top with a spoon. Cover with loosely tented aluminum foil and refrigerate for at least 3 hours or overnight.