Sift the powdered sugar into a mixing bowl to remove lumps.
Gradually add milk and mix until smooth.
Stir in the corn syrup for a glossy finish.
Add vanilla extract and mix well.
Adjust the consistency by adding more milk or sugar as needed.
Divide the icing into bowls for coloring.
Mix in food coloring to achieve desired shades.
Transfer icing to piping bags for easy application.
Decorate cooled sugar cookies with the icing.
Allow icing to dry completely before serving.