Uprooted is Naomi Novik's first stand-alone fantasy novel (she's well know for her Temeraire series), and it is a delightful story with tons of appeal. I was impressed by the way she captured the feel of a familiar fairy tale while still telling an inventive and original story. I especially enjoyed the way that Novik handled the romantic subplot (warning: things do get rather steamy).
And because I can't limit myself to just one fantasy recommendation, here are two of my other favorites from 2015:
~Sarah, Adult Services