Reduce oven temperature to 350°F. In large bowl, stir condensed milk, egg and peanut butter until smooth. Stir in chopped peanut butter cups. Pour in crust over caramel mixture. Bake 30 to 35 minutes or until filling is set. Refrigerate 1 hour. Drizzle melted candy bar and reserved caramel over top of pie. Sprinkle with 1/4 cup peanuts. Lightly sprinkle with kosher salt. Cover and refrigerate any remaining pie.