Book 1 of Agatha Raisin
 
High-flying public relations supremo Agatha Raisin has decided to take early retirement. She's off to make a new life in a picture-perfect Cotswold village. To make friends, she enters the local quiche-making competition - and to make quite sure of first prize she secretly pays a visit to a London deli.

Alas, the competition judge succumbs after tasting her perfect quiche, and Agatha is revealed as a cheat and potential poisoner. Definitely not the best start. So Agatha must turn amateur sleuth - she's absolutely got to track down the real killer!
M C Beaton