Lady Arianna Hadley has led a colorful, and hard, life because of the choices her father made. After his murder Arianna takes on a disguise and the role of French chef in an aristocratic household, both so that she can support herself and to investigate. Her specialty is making incredible creations from the newest food fad in Regency England, chocolate. Her precarious existence is threatened when the Prince Regent takes ill after consuming one of her desserts.
Allesandro De Quincy, the Earl of Saybrook, is a chocolate expert which is what brings him to Arianna's kitchens to investigate. He immediately knows there is something off about the French chef and quickly realizes that "he" is a "she" which makes him doubly suspicious. Though Saybrook is not sure he can trust the woman who has infiltrated the household, he needs her insider knowledge to figure out what is going on and the two form an uneasy alliance.
There are cozy elements here including chocolate facts and knowledge at the start of each chapter from the diary of a Spanish noblewoman:
"Chocolate was served during religious rites and celebrations. It was often mixed with flavorings such as vanilla, cinnamon, allspice, chilies, hueinacaztli--a spicy flower from the custard apple tree--and anchiote, which turns the mouth a bright red! The Aztec also believed that the dried beans of the cacao tree possessed strong medicinal properties. Indeed warriors were issued cacao wafers to fortify their strength for long marches and the rigors of batttle."
The cozy aspects are balanced (which works a bit better for me) by complicated characters and a plot that delves into finance and politics. There are two more books in the series if you enjoy this one as much as I did.