In a microwave safe bowl, combine 1/2 cup butter and coarsely chopped unsweetened chocolate. Melt in 30 second increments stirring after each time until it is melted and smooth. Set aside and allow to cool slightly.
Preheat oven to 350 degrees. Line a 9x13 inch pan with aluminum foil and spray lightly with cooking spray. Set aside.
To make the brownie layer:
In a medium sized mixing bowl, whisk together flour, baking soda, and salt. Stir 1 cup of sugar into the melted chocolate. Stir in eggs and vanilla. Combine chocolate mixture with the flour mixture and mix until just combined. Pour batter into your 9x13 inch pan and spread evenly. Bake for 15- 17 minutes. Cool Completely.
For the caramel layer:
In a microwave safe bowl add the caramels, and 2 tablespoons evaporated milk. Microwave on high stirring every 30 seconds in between until melted and smooth. Stir in chopped peanuts.Spread the caramel mixture over the cooled brownies. Put in the freezer to let it set before putting the nougat layer on.
For the nougat layer:
Add 1 1/4 cup sugar, and remaining evaporated milk (1/2 cup plus 2 tsp), and 1/3 cup butter. Turn to medium high heat and bring to a boil stirring frequently then reduce to medium. Simmer uncovered for 5 minutes without stirring. Remove from heat and stir in marshmallow cream and peanut butter. Remove your pan from the freezer and spread the nougat layer on top of the caramel layer. Place the pan back in the freezer.
For the chocolate layer: In a microwave safe bowl combine chocolate chips, butter and heavy cream. Heat in 30 seconds increments stirring every time until melted and smooth. Spread evenly over the nougat layer. Put back into the freezer to let the chocolate layer set up. Cut into squares and store in the refrigerator.