2 cups powdered sugar
2 to 3 tablespoons milk
1 tablespoon light corn syrup
1/2 teaspoon vanilla extract
Food coloring, optional
Whisk powdered sugar, milk, corn syrup, and vanilla until smooth
Add more milk for thinner frosting
Add more powdered sugar for thicker frosting
Stir in food coloring if desired
Spread or pipe onto cooled cookies
Let frosting set before stacking cookies