Okay. I checked the book and it does not give a source...
The ingredients list calls for "6 edible rose transfers (available online)." In the directions, after they are unmolded, it says to "apply a rose transfer to the top of each panncotta holding each transfer in place for at least 30 seconds and delicately rubbing the reverse side to ensure that the image transfers."
I ran across a comment from an online review asking where you could buy them and someone posted that the author's store sold them and included the link. However, the comment was from a few years ago and there is not currently an online shop at her website.
Sorry I could not be of more assistance. Let me know if you find them. I would be curious to know what type of transfer it is.