Book ~ "Fatal Fruitcake" (2012) Mary Kay Andrews (Kathy Hogan Trocheck)

From Goodreads ~ Atlanta cleaning lady/private detective Callahan Garrity, the protagonist of the author's eight critically acclaimed mysteries, returns from a long hiatus in this short story to track down the source of a killer fruitcake--and in the process discovers that some forms of Christmas spirit really can be lethal. 

Callahan used to be a police officer and changed careers when she bought House Mouse, a cleaning service that she runs with her mother, Edna ... but she still does private investigating on the side.

It's the Christmas season and Callahan and Edna are putting up their tree.  Callahan gets a call from Jacky, one of her House Mouse employees, that while cleaning after an office party, she came across a dead body in the boardroom.  Panicked she called Callahan who advises her to call the police.  When Callahan arrives, the coroner has found a piece of fruitcake lodged in the dead guy's throat and deems it death by asphyxiation.  Callahan doesn't believe this and investigates and discovers what really happened.

This is a short story in the Callahan Garrity Mystery Series. 

 Also included is the author's recipe for a not-so-fatal fruitcake.