She was born in Cornwall and grew up on Restronguet Creek. She studied Experimental Psychology at St Catherine's College, Oxford, before moving back to the West Country. She now lives in Falmouth with two imaginary cats, fantasising about getting a real one.
In 2011 Rosen was an aspiring author. Writing was a hobby. The following January sales of her books took off. Readers have now downloaded over a quarter of a million copies of her books.
Rosen has a variety of books in print including My Granny Writes Erotica - Threesome, Pompomberry House and two Seesaw collections, as well as over a dozen digital titles.
In 2013 she founded the Smelly Troll series - children's chapter books written by Rosen and illustrated by Katie W. Stewart. The series, which begins with The Troll Trap, has inspired hundreds of children to get involved in creative writing.
Rosen writes in a variety of genres with a strong leaning towards comedy. She has also dabbled in psychological fiction and mystery writing.
She loves wild swimming, interesting boots, quiffs, 'sampling' chocolate and cooking tasty treats. She dislikes house spiders, seagulls making a racket and doing laundry.