Ingredients:
- 4 cups (480g) powdered sugar, sifted
- 2.5 tablespoons (37.5ml) whole milk
- 2 tablespoons (30ml) light corn syrup
- 1 teaspoon (5ml) pure vanilla extract
- 1 pinch fine sea salt
- Gel food coloring as needed
Instructions:
- Sift the powdered sugar into a large glass mixing bowl to remove all lumps for a smooth finish.
- Whisk in 2 tablespoons of milk, the corn syrup, vanilla extract, and salt. Stir until the mixture is thick, smooth, and free of dry sugar streaks.
- Test the consistency using the 10-second rule: run a knife through the icing; if the line disappears in exactly 10 seconds, it is ready for flooding. Adjust with 1/2 teaspoon of milk to thin or additional sugar to thicken.
- If using color, add gel food coloring and stir gently to avoid incorporating air bubbles.
- Transfer icing to piping bags. Outline the cookie edges first, then flood the center. Use a toothpick to pop any surface air bubbles.
- Allow cookies to sit on a flat surface. The icing will be dry to the touch in 4-6 hours and fully hardened for stacking overnight.