Who is the recent Nancy Drew writer who wrote 50 books?

The recent Nancy Drew writer who wrote 50 books is Carolyn Keene.

However, it's important to note that "Carolyn Keene" is a pseudonym used by a series of different authors over the years. The most recent author to write under the "Carolyn Keene" name is Stefanie London, who started writing the books in 2010.

It's also important to note that while Stefanie London has written 50 Nancy Drew books, there have been many more Nancy Drew books written over the decades by various authors.