In a mixing bowl, combine the powdered sugar and meringue powder.
Add warm water gradually, mixing until smooth.
Incorporate the vanilla extract.
Stir until the icing reaches a thick, spreadable consistency.
If using, add corn syrup for a glossy finish.
Divide the icing into separate bowls for coloring.
Add food coloring to each bowl and mix until desired shades are achieved.
Transfer the icing to piping bags for easy decorating.
Outline cookies first with a thicker icing, allowing it to set.
Fill in the centers with thinner icing and use a toothpick to spread it evenly.