Is your royal icing still wet after drying overnight? It is sticky or tacky to the touch? Does it look foamy and is it covered in little bubbles?
The problem is…WATER.
I addressed this in my TROUBLESHOOTING post. (There are a lot of Royal Icing Q and A's there.)
(See more of the finished St. Nicholas Day cookies here.)
CLICK TO READ MORE…more sugar this way!