When Araminta Greaves Traded Her Dignity for Bliss. Wainwright Sisters, #1

Tropes: Holiday romance, Mature main characters (hero-42, heroine -38), forced proximity (snowed in together) single father, reverse Cinderella. A decade ago, Araminta's father foisted her off on the elderly county squire with her prize herding dog. The squire's dead and she's living on the forebearance of her insufferable step-son and his wife as an unpaid housekeeper and governess to their daughters in exchange for room and board.
She's been tasked with organizing the holiday party and when it ends in disaster because of food poisoning, an ornery barn cat and a crashing tree, she seeks solace in the barn. She falls asleep over a pile of puppies and when she wakes up she's cradled in the arms of a local farmer. He's a single father of four rambunctious girls and a Crimean war hero. He's inexorably drawn to the quiet woman who's always standing in the shadows.