Step 1

Place 2 cups powdered sugar, 2 tablespoons whole milk, and 1 tablespoon light corn syrup in a medium bowl and whisk until smooth. Drizzle a bit of the icing off of the whisk or a spoon over the bowl of icing; if the icing holds its shape for a few seconds before melting back into the icing, it's ready to use. If it is too thick, whisk in 1/2 teaspoon milk, checking consistency before adding more until the icing is the right texture.

Step 2

Divide the icing into bowls and use food coloring to dye icing as desired. Let the icing dry overnight on decorated cookies.

Step 3

Use the icing immediately or cover the surface with plastic wrap until ready to use. (See storing instructions below.)