Aku no Taizai: Akujiki Musume Conchita

Book two of the Aku no Taizai series.
Banica Conchita, a woman who, at one time, ate only the most delicious and exquisite food. Now, however, her tastes have evolved so that she wants something new and grotesque every day, and nothing enters or leaves her palace. The fifteenth personal chef of the year asks for a brief vacation, but she, angry, decides to eat him. Running out of food to eat, she ends up eating her butler and maid, and when everything has gone, she ends up eating herself—which nobody else will ever know what it tastes like.