A classic, simple royal icing recipe that can be used to fancy up cookies, cakes, and all sorts of treats.
Royal icing is a bit of trial and error to find the consistency that you like to work with (thick or runny). Rule of thumb is one egg white to one cup of icing sugar. Remember when the icing is runny the icing will spread out.
Also the icing needs lots of time to air-dry (I like to let my piped cookies air-dry overnight).
Find it online: https://bakingforfriends.com/christmas-sugar-cookies/