Easy Cowl with Button (in round??)

I’d like to make something special for my sister’s upcoming birthday – I bought some very expensive and lovely Artyarn, beaded rhapsody (a mix of mohair, silk, and little crystal beads). I was hoping I could make it into a cowl, but am having trouble finding a pattern that will be easy enough for me to do and still suited to the yarn.

I can just do it all in stockinette, which does look nice with this yarn, but is kind of dull. Plus, lots of purling, which I do not love. (I could avoid the purling by doing it on circular needles, but she doesn’t like pulling things over her head, so I was hoping to do the kind of cowl you button instead – which I think means I have to use straight needles?).

So that’s my question – what would you suggest to make a buttoned cowl, in a very fancy yarn, that doesn’t involve a ton of purling, and which is simple enough for a relative beginner?

Help? (With crochet, I’d just make up a pattern, but I still don’t really know how to do that in knit.)