I’m a little confused.  I read in Rose’s book that grease breaks down royal icing.  Does that also apply to piped royal icing on top of buttercream frosting?  I have a friend that I’m making a baby shower cake and she want buttercream with a royal icing message on it.  Will it melt on it? Maybe I should use something else???

ROSE V:
  Hello again. Rose, I believe Miss Rose means FAT from the EGG YOLK. As you know, sometimes when separating whites from the shell the yolk breaks & a slight amount of the yolk gets imbedded in the whites. This small amount of fat can play havoc with the royal icing. I hope this explanation will put your mind at ease.
Good day my friend.

  ~FRESHKID.

That makes sense.  Same concept as when whipping meringue you canmixit with butter to make meringue buttercream, but not while whixking the whites to make the initial meringue.  I will try and thanks for your advice I’ll keep it in mind and make a trial mini cake and see what happens

Royal icing will stay dry and hard as long as it isn’t allowed to absorb any moisture (from the air or any other source, even buttercream).  If possible, wait until the last minute to add ther dried royal icing decorations to your cake.

Got it!  Will do that and thanks a bunch!

~FRESHKID - 29 January 2008 11:26 AM

ROSE V:
  Hello again. Rose, I believe Miss Rose means FAT from the EGG YOLK. As you know, sometimes when separating whites from the shell the yolk breaks & a slight amount of the yolk gets imbedded in the whites. This small amount of fat can play havoc with the royal icing. I hope this explanation will put your mind at ease.
Good day my friend.

  ~FRESHKID.

The fat from the butter in the buttercream is really the culprit!  Over time, the royal icing will begin to “melt” and disintegrate.  As for how long it takes before it happens, your mileage may vary based on where the cake is stored (high humidity or low humidity refrigerator) and how far in advance you pipe the royal icing onto the buttercream.