Sift together flour, cocoa and salt.

Melt together butter and unsweetened chocolate over low heat. Remove from heat and cool to lukewarm.

Add eggs,vanilla and sugars. Stir very well until sugars are dissolved.

Gently fold in dry ingredients (and chocolate chips if you are using them)

Pour batter into a 9 inch square baking pan that has been lightly greased and lined with parchment paper.

Bake for about a half hour at 350 degrees F or until the surface of the center of the brownies appears dry and firm. The toothpick test will not work for this recipe but it will tell you if the middle is still liquid. Do not over bake these brownies or they will be dry rather than moist and chewy.

As soon as they come out of the oven, sprinkle the top of the brownies evenly with the miniature marshmallows.

Turn your broiler on low, place the brownies on the center rack or a little lower, and lightly toast the marshmallows. Watch them carefully.

Remove the brownies from the oven and allow to cool completely in the pan.

Drizzle the melted chocolate evenly over the marshmallow layer.

It is best to at least partially freeze these cookie bars to harden the marshmallow layer on top. This makes them much, much easier to cut but you will still need to clean your serrated knife often as you cut out the cookie bars. Using the parchment paper to lift the entire batch of cookie bars out of the pan and onto a cutting board is also very helpful.

These freeze very well in airtight plastic containers.