Stand mixer with a whisk attachment and mixing bowl
4cupsicing sugar (also known as confectioner's sugar or powdered sugar)approximately 1 pound
1teaspoonvanilla extract or other flavoringoptional
gel food coloringoptional
Add 4 cups of icing sugar to the mixer and mix for a few seconds to eliminate any clumps. Or you can sift it ahead of time.
Add 3 Tablespoons meringue powder, 1/2 cup of warm water and 1 teaspoon vanilla extract.
Mix on low speed until combined.
Increase the speed to medium and continue to beat the icing until it holds soft peaks, about 5 to 8 minutes
Adjust The Consistency
For hard decorations, beat until the icing forms hard peaks.
For outlining and writing, add a few drops of water at a time (mixing well between each addition) until the icing closes a gap cut with a knife in 15 seconds.
For flooding, add a few drops of water at a time (mixing well between each addition) until the icing closes a gap cut with a knife in 10 seconds.
To add color, put some of the icing into a glass or metal bowl and add gel food color in a little bit at a time, mixing well in between each addition until the desired color is obtained.
Let the icing dry for 4 to 6 hours.
Use as little food coloring as possible to prevent the icing from having a bitter taste
Color will darken as it dries
To ensure the icing has completely dried, leave it overnight before stacking cookies or adding more icing colors
If icing is too thick, add a few drops of water at a time, mixing well between additions, until the desired consistency is obtained.
If icing is too runny, mix in some thick icing or icing sugar until it becomes thicker
How To Store Royal Icing
Royal icing can be stored for up to 3 days at room temperature, up to a week in the refrigerator or up to 3 months in the freezer.
To store it at room temperature or in the refrigerator, put a layer of plastic wrap over the icing in the bowl so that the plastic is in direct contact with the top of the icing. Then push out all of the air pockets.
To store it in the freezer, put the icing in Ziploc bags and push all the air out so you know it's air tight.
Bring it back to room temperature before starting to use it.
After sitting for a couple of days, Royal Icing may separate. Just mix it for a few seconds to bring it back to its normal consistency.
Royal Icing: Sugar Cookie Icing That Hardens from https://www.entertainingdiva.com/recipes/royal-icing-recipe/