Prepare brownie batter according to box directions. You want to bake them in an 8x8” pan. If you are using a family style (9x13” pan) mix, you will have extra batter. You can make the rest in a loaf pan or a muffin tin.
Line your pan with foil and spray with cooking spray. Bake and cool brownies completely.
Remove brownies from pan and remove foil. Add new foil to the 8x8” pan and spray sides liberally with cooking spray (the milky way mixture is very sticky!) Add the brownies carefully back into the pan.
Melt chocolate chips in a microwave safe bowl, about 30 seconds on HIGH. Stir to melt. You can microwave in increments of 10 seconds more if needed. Stir fluff and 1 1/2 tablespoons of evaporated milk into the melted chocolate chips. Pour and spread immediately over brownies in pan.
Melt caramels and 2 remaining tablespoons evaporated milk in in the microwave in 30 second increments, stirring after each. Once they are melted and smooth, pour and spread over chocolate/fluff mixture. Chill until firm, about 2 hours.
Once the caramel has firmed up (you should be able to leave a finger indent, but you won’t come away sticky), remove the bars from the pan and carefully remove the foil. Set the brownies on a cutting board.
Spray your knife with cooking spray and cut into squares. You will need to wipe and respray your knife after every two cuts or so.
You have two options for the chocolate covering. One, melt your chocolate melts in a large bowl and dip each square to completely cover. (If you do this method you will likely need the entire amount of chocolate.) Tap to remove excess chocolate and pace on a wax paper lined cookie sheet. Chill to harden.
The other option is what I did, because dipping is tedious and I don’t like doing it. Place squares on a rack set over a cookie sheet. Melt your chocolate (about 1 cup at a time) and spoon a little over the top of each square. Use the back of the spoon to spread it and make it drip down the sides. You will use less chocolate this way. Chill to harden.