Sauce: Add the cream, brown sugar, corn syrup, cocoa powder, salt, and vanilla extract to a heavy-bottomed saucepan over medium heat. Reduce the heat to a simmer and add the chopped chocolate. Stir continuously until the chocolate is melted and the sauce has thickened, roughly 3 to 4 minutes. Let the sauce cool for 10 minutes before serving.
Pie: In a large bowl combine the cream cheese, 3/4 cups confectioners' sugar and the peanut butter until the mixture is light and fluffy, about 3 minutes.
In a separate bowl, whip the heavy cream until thick and light. Add the remaining 2 tablespoons confectioners' sugar and vanilla extract. Continue to whip until stiff peaks form.
Carefully fold the whipped cream into the peanut butter mixture. Pour the batter into the pie shell, sprinkle with the shaved milk chocolate and freeze for 4 hours.
If desired, serve with the hot fudge sauce, whipped cream, and chopped peanuts.