place the cookies upside down on a cookie sheet (I suggest using parchment paper for easy clean up if one falls over), then place a marshmallow on each cookie and bake in the center of the oven for 3-4 mins.
To get a nice golden brown I like to turn on the broiler for just a min more (or two if you like them more dark)
finish off by adding chocolate on top of the marshmallow while they are still warm...