In a mixing bowl, combine powdered sugar and meringue powder.
Add 5 tablespoons of water and vanilla extract to the dry ingredients.
Mix on low speed until well combined.
Increase speed to medium and beat for 5-7 minutes until glossy and stiff peaks form.
Adjust consistency by adding more water if too thick.
Divide icing into bowls for coloring.
Add food coloring and mix to achieve desired hues.
Transfer icing to piping bags or squeeze bottles.
Decorate cooled sugar cookies with icing.
Allow icing to dry completely for several hours.