In a bowl, mix together the pretzel crumbs (these are easy to make smaller in a food processor), brown sugar, and melted butter. Press into a greased 9 1/2-inch pie plate. Bake in preheated oven for 8-10 minutes, or until the pretzels become fragrant. Cool.
In a large, deep bowl, beat together the whipping cream, confectioners' sugar, and 1 teaspoon vanilla extract until stiff peaks form. Set aside.
In another bowl, beat together the peanut butter, cream cheese, sugar, and 1 teaspoon vanilla extract. Once this has been fully mixed, blend in 1 cup of the whipped cream. Using a large spatula, fold in another cup of the whipped cream.
Pour about 1/2 cup of the fudge sauce into the bottom of the cooled pie crust (reheat the sauce if necessary). Using a spoon, spread it all over the bottom and sides of the pie crust.
Scrape the peanut butter mixture into the pie crust, spreading it into an even layer.
Top the pie with the remaining fudge sauce and whipped cream, or top each slice just prior to serving. Cool in the refrigerator for at least 1 hour before serving. Store remaining pie covered in the refrigerator.
Recipe by The Baking Beauties at http://www.thebakingbeauties.com/2014/02/peanut-butter-pie-with-chocolate-covered-pretzel-crust.html