Line 8" square baking dish with aluminum foil. Spray with cooking spray. Set aside. Preheat oven to 350 degrees F.
In a small mixing bowl, whisk together flour, baking soda and salt. In a large mixing bowl of a stand mixer, beat together butter and both sugars until creamy.
Add pudding mix, egg, vanilla and mix well. With the speed on low, gradually add the dry ingredients. Stir in butterscotch morsels.
Pat the dough into prepared pan.
Bake 13 - 15 minutes, or until the edges start to brown. The center might be still soft, but it will set as it cools.
Lay a kitchen towel on the floor and drop the pan with cookie dough from 2 - 3 inches. See notes.
Cool the cookie dough completely in the pan, on wire rack.
For nougat: In a medium saucepan, melt butter. Add sugar and evaporated milk and stir. Bring to a boil and cook for 5 minutes, stirring constantly. Remove from heat. Immediately, stir in marshmallow fluff and peanut butter, vanilla and peanuts ( if using ). Mix until smooth. Spread over the cookie base.
Refrigerate 15 minutes or until set.
Melt caramels with heavy cream in a microwave safe bowl. Stir until smooth. Spread over nougat layer. Refrigerate 15 minutes.
For homemade caramel sauce: cook together butter, sugar and cream. Bring to a boil. Cook for 2 minutes stirring constantly. Cool completely on the counter. Spread over nougat layer. Refrigerate for 15 minutes.
For frosting: In a microwave safe bowl, melt together butterscotch morsels, milk chocolate morsels and peanut butter. Stir until smooth. Spread over the caramel. Smooth out the top.
Refrigerate at least 1 hour or until the frosting is set.
Let stand it room temperature for 10 minutes. Cut into 1" squares.
Store airtight in refrigerator.
Notes
The cookie dough is quite sticky, so to pat it into a bottom of your pan, try using a leftover butter wrapper. It's already greased and it will make it easier to smooth the top out. For the caramel layer, I used my homemade caramel sauce, but feel free to melt store bought caramels with heavy cream. The instructions say to drop the pan with cookie dough onto a surface. Apparently, this creates more chewy dough.