The Lady and the Highwayman by Sarah Eden

 Elizabeth Black is a very proper headmistress of a respectable girl's school who has a secret.  She is also a writer of cheap "penny dreadful" novels.  She writes under the pseudonym of Mr. King, and her books are very successful.  One day she meets Fletcher Walker, another writer of penny dreadfuls, who has risen from being a street urchin to a level of some social status.  Walker is also the secret leader of a group of men who try to help street children find a better life through sometimes less-than-legal means.  As Elizabeth and Fletcher become more and more attached, both struggle to hide their secrets. 

I think this is probably Ms Eden's most popular series.  I enjoyed it very much.  The story is written from the point of view of both Fletcher and Elizabeth in alternating chapters, but then there are chapters from each of their penny dreadful novels.  The novels within a novel is handled in a clever way that leads to the resolution of the plot.  I started this book because I was fed up with another book I was listening to, The Power of Fun by Catherine Price.  That book wasn't much fun at all (so far it's been a long rant about how cell phones are ruining our lives.  I may still finish it, but I may not), but this one was. (2019, 384 p)