I could not find a book with a Christmas title for the meme at Mysteries in Paradise but the superb Bill James novel Roses Roses is set around Christmas, so I hope that counts.
Megan, the wife of Chief Superintendent Colin Harpur, is murdered in a station car park on her return from a shopping trip to London. Colin Harpur and Desmond Isles investigate the case by their own very different methods, while all the characters in the story are brilliantly unsavoury. The world of the police that Bill James depicts in the quirky Harpur and Isles series is probably more accurate than most people in the job would want to admit.
Isles invites his subordinate Garland to Christmas dinner.
'Francis do you want to attend, with companion of course, as long as he-she washes under the arms? You still hetero? I pry only so we can alternate gender placings at the table, on which Sarah's fussy.
I would have asked earlier but had to mull over at length whether I really wanted a thin-lipped arrogant prat like you present on such a goodly occasion. But obviously Harpur will be there, so why not another who's had my wife?
Christmas is hardly a time for mean spirits, surely.'
'Thanks so much , sir' Garland replied. 'It's very kind but i always go to my mother's.'
'How sweet,' Isles said.