When the brown sugar has completely dissolved, remove from heat and let cool completely.
Take a chopstick or sharp point of a knife and create a hole in each cutout at the top of the heart right below where the two arches come together.
Switch to the star tips and pipe a stars border around the edges of each heart. You can use one color or alternate 2 or three colors. Add some decorating inside the border on the face of the cookie, if you like.
WARNING! The icing recipe contains raw egg whites.