Step 1

Combine the 1/3 cup peanut butter, confectioners' sugar and heavy cream in a medium bowl and beat with an electric mixer until light and creamy, about 2 minutes. Spoon the mixture into the bottom of the pie crust and smooth evenly. Freeze until slightly firm, about 20 minutes.

Step 2

Spoon the softened ice cream on top of the peanut butter cream and spread to fill the pie crust. Freeze until very firm, at least 2 hours.

Step 3

Mound the marshmallows in the center of the pie and torch them with a kitchen torch; you can also broil them in the oven, but watch them carefully if you do. Warm the remaining 2 tablespoons peanut butter in the microwave until pourable, about 30 seconds. Drizzle the chocolate syrup and peanut butter over the pie. Freeze until ready to serve.