Bowen, Rhys. Royal Spyness mysteries #17

"Georgie, back home at her estate in Eynsleigh, impatiently awaits the birth of her baby. But she has plenty to occupy her: her new chef, Pierre, has arrived from Paris, and Sir Hubert, who owns Eynsleigh, is back from his latest expedition. It's time for Georgie to throw her first house party to celebrate his return and show off her new chef. The dinner party is a smashing success. Sir Mortimer Mordred--famous author of creepy Gothic horror novels--is one of the guests. He recently purchased a nearby Elizabethan manor nearby because it has a famous poison garden. After the dinner, Sir Mortimer approaches Georgie and asks to borrow her new chef for his upcoming party, and Georgie and Darcy, her dashing husband, are invited! The tour of the poison garden is fascinating, as is Sir Mortimer's laboratory. Shockingly, just after the banquet several of the guests become sick. And one dies, apparently poisoned by berries from the garden. But how could this be when they all ate the same meal and the same delectable dessert? Georgie has to find the culprit to save her new chef and her own reputation--all before her bundle of joy arrives!"--