Showing Trick or Treat by Kerry Greenwood

Corinna Chapman, amateur sleuth, baker extraordinaire and proprietor of the Earthly Delights Bakery, returns for her fourth criminally entertaining and delicious adventure.
When a cut-price franchise bakery opens its doors just down the street from Earthly Delights and crowds flock to purchase the bread, Corinna Chapman is understandably nervous. Meanwhile, the gorgeous Daniel's old friend Georgiana Hope has temporarily set up residence in his house, and it doesn't take Corinna long to work out that she's tall, blonde, gorgeous and up to something. Daniel is making excuses and Corinna is worried about his absences and also the strange outbreak of madness which seems to be centred on Lonsdale Street.
Will Corinna win through a maze of health regulations, missing boyfriends, sinister strangers, fraudulent companies and back-alley ambushes? Or will this be the end for the Earthly Delights Bakery?