List authors by most recent poster

I’m trying to list authors for a blog that has ~60 authors. I’d like to sort the author list by most recent authors at the top of the list.

How could I obtain this?

I tried a query to list recent posts and only display author names for those posts but how would I not duplicate an author if they make more than one posts? (ex: 3 posts in a row, but only show that author as per their most recent post.)

Thanks in advance.