Heat frosting in microwaveable bowl at 15 second intervals until frosting is soupy.
Puddle frosting on to cookies using a spoon, spread with back of spoon if needed.
Spray microwaveable plate with Pam. Place marshmallow on plate, leaving space between each (room for expansion). Microwave until marshmallow puffs up slightly, but not too much.
Immediately place marshmallow on frosting. Press down on marshmallow.
If the frosting you have does not have a fine tip, squeeze in to a Ziploc baggies and cut a very small hole in the corner for a frosting tip.
Add eyes, a note, buttons, arms and a scarf!