Preheat oven to 325 degrees. In food processor or blender process cookies until finely ground. Add butter and mix together completely. Press crumb mixture into the bottom of a 8x8 inch baking pan. Bake 10 minutes. Cool to room temperature.

Melt chocolate in double boiler over slightly simmering water or microwave chocolate, stirring every 30 seconds, until completely melted. Pour half the melted chocolate into pan and smooth evenly over crust. Place pan in refrigerator. Keep remaining chocolate warm.

To prepare peanut butter filling, blend peanut butter and butter together until smooth using a food processor or electric mixer. Slowly beat in powdered sugar and then add vanilla. Beat until smooth. Spread peanut butter filling over chilled chocolate layer. Finish by pouring the remaining warm chocolate over filling and spreading smooth. Chill in refrigerator 1 hour or until firm. Cut into bars and serve.