Add dry ingredients to creamed mixture alternately with milk.
Form into 1 1/2 inch balls and bake on greased cookie sheet for 8-10 minutes. Press 1/2 a marshmallow onto each cookie, bake an additional 2 minutes, or until marshmallow is melted.
Combine frosting ingredients. Spoon frosting over each cooled cookie. (Or for a more dazzling effect, pour frosting into the corner of a ziplock bag, snip off the corner, and drizzle frosting across cookie.).