For the cookie base: Preheat oven to 350 degrees. In a small bowl, combine flour, baking soda, and salt. Beat butter, brown sugar, and sugar in a large mixing bowl until creamy. Add eggs, pudding mix, and vanilla; mix well. Gradually beat in flour mixture. Stir in butterscotch morsels. Spread and pat down dough evenly into parchment paper-lined 17x11x1-inch pan. Bake 10-11 minutes or until light golden brown. Carefully hold pan 2-3 inches above a heat resistant surface and allow pan to drop. (This creates a chewier cookie base.) Cool completely in pan on wire rack.
For the nougat filling: Melt butter in a medium saucepan over medium heat. Add sugar and evaporated milk; stir. Bring to a boil, stirring constantly for 5 minutes. Remove from heat. Stir in marshmallow crème, peanut butter and vanilla. Add peanuts; stir well. Spread nougat mixture over cooled cookie base. Refrigerate for 15 minutes or until set.
For caramel layer: Combine caramels and cream in a medium saucepan.
Cook over low heat, stirring constantly until caramels are melted and mixture is smooth. Spread caramel mixture over nougat layer. Refrigerate for 15 minutes or until set.
For icing: Melt milk chocolate morsels, butterscotch morsels and peanut butter in a medium microwave-safe bowl on medium high for 1 minute; stir. Microwave at additional 10-to-20- second intervals, stirring until smooth. Spread icing over caramel layer. Refrigerate for at least an hour.
To serve, let stand at room temperature for 5-10 minutes. Cut into 1-inch pieces. Store in an airtight container in refrigerator. Yields 15 dozen pieces.