Icelandic Cake

So a friend of mine's girlfriend visited Iceland and fell in love with a cake they make there.  I do not know the name but she was able to get the recipe from the bakery.  My problem is a specific ingrediant "gluten" which I am not sure what they are asking for.  Below is what was sent to me.  Anyone ever hear of this?  I would really like to try to make it but really need help getting this together.  They also sent me a picture I posted below if it helps. 

Appreciate any help (I don't know any Icslandic's to ask)