When I originally read and rated this story, I gave it three stars. After reading this time, I've definitely revised how much I like this novella. I'm always leery of novellas with characters I don't really know or haven't yet met because novellas are short spaces to write an entire romance. Often authors spend more time on on the plot than they do on the characters and romance which leaves me less than satisfied.
That's not the case with Once Upon a Winter's Eve, though these characters are basically strangers. Violet shows up in A Night To Surrender, but only briefly, and Christian is entirely new. Tessa Dare smartly doesn't give us a separate plot for these characters or develop an entirely new romance between them. Violet and Christian knew and had a relationship before the story opens. This is the story of their reunion and what's happened since he left for the West Indies--which turns out he went to war.
Because the plot is literally Christian being mistaken for a French soldier who speaks a dialect only Violet can understand, it puts their relationship at the center and that's really smart. Violet doesn't know if she can trust him, and Christian is trying to beg her forgiveness and understanding -- it's a great small-scale plot for a novella.
Character-wise, these are both shining examples of people I like to read about. Christian is layered, flawed, and determined. Violet is quick and capable of holding her own against basically the entire world. The romance is great and fun to read. This is one of the best novellas I've read in a long time.