Beat in the corn syrup and vanilla extract. Beat on low until everything is blended. Turn the mixer to medium-high speed and mix until the icing forms stiff, glossy peaks, about 5-7minutes.
Let the icing sit at least 30 minutes using if coloring it with a dark gel color, like red or black.Icing can be thinned with water depending on the desired consistency. Keep the icing covered with a damp paper towel to keep from drying out.
Notes
Makes 3 cups of icing.
Keyword cookie icing, decorating icing, royal icing