Sift powdered sugar into a mixing bowl to ensure a lump-free base.

Add milk or water gradually, starting with 2 tablespoons. Stir well after each addition until you reach a thick but pourable consistency.

Stir in light corn syrup and vanilla extract until combined.

Color the glaze if desired by adding gel food coloring until you reach your preferred hue.

Apply the glaze to your cookies using a spoon, piping bag, or squeeze bottle.

Let dry at room temperature for 8–12 hours.