Pre-heat the oven to 350 degrees. Line a 13x9 baking pan with foil with the foil extended over the edges.
Prepare the brownie mix according to the package. Pour the batter in the prepared baking pan and bake according to package. Then let cool. Once the brownies are cooled using your hands smash them down to make room for the peanut cream mixture.
Next, in a sauce pan melt the sugar, 1/3 cup butter, and 1/2 cup of the evaporated milk.
Bring to a boil stirring till the sugar is dissolved. Reduce to a medium heat. Simmer for 10 minutes. (using a spatula make sure to scrap the bottom while simmering so it won't burn)
Remove from the heat and add the marshmallow cream, and peanut butter till smooth. Then add the chopped peanuts.
Carefully pour over the brownies spreading to the edges.
Place in the freezer for 20 minutes.
For the caramel layer. Place the caramels and remaining evaporated milk which is about 2 Tbs in a bowl. Microwave 1 1/2 to 2 minutes until caramels are melted.
Pour the caramel over the peanut cream mixture spreading to the edges. Return the pan to the freezer for 10-15 minutes.
Next, the chocolate layer. In a small bowl microwave the chocolate pieces for 1 minute or until melted and smooth. Pour chocolate over caramel layer. Spread evenly to edges. Chill 2 hours or until firm.
To transfer out of pan. pull up on the extended foil and lift uncut bars out of the pan. Transfer to cutting board to cut into squares.