I love the ease and taste of MMF on cookies. This week, however, I made a simple pumpkin shape cookie and covered it with orange MMF. I then piped the veins and stems of the pumpkin in royal icing. I let the cookies dry overnight and when I packaged the cookies the next day the royal icing just crumbled off. Any thoughts on why this happened or advice on how to avoid it in the future would be appreciated. Thanks!