The Cat Who Loved Mr. Darcy by Laura Nickleby

Elizabeth Bennet’s sharp eyes have often seen through charm and pretension—but her most trusted judge of character is her grey-and-white tomcat, Sophocles. Dignified, discerning, and famously unsentimental, Sophocles grants his affection only to those he deems worthy.
At Longbourn, family and guests alike must submit to his quiet, unyielding inspection. He has hissed at fools, scratched at scoundrels, and turned his back on flatterers. Suitors fail spectacularly under his stare—until one man surprises Elizabeth entirely. Fitzwilliam Darcy, proud and aloof, is the last person she expected to win Sophocles’s rare approval.
As tensions rise and old grievances are confessed, Elizabeth must decide whether to trust her own heart and the cat who has never yet been wrong.

A tender Regency romance of quiet evenings, fierce loyalty, and the truth no one can deny: If you love me, you must love my cat.