Add salt, cocoa, hot cocoa mix and flour and mix until well incorporated. Do not over mix.
Pour into greased 9x13 inch baking pan and bake at 350 degrees F for 22-25 minutes.
While baking, cut large marshmallows in half.
Once brownies have cooked, place halved marshmallows uncut side up, over tops of brownies. Place under broiler for 1-2 minutes until marshmallows are golden and nicely toasted. Watch carefully so as not to burn them.