Harlequin SuperRomance #1134 (Raising Cane #3) Jackson's Girls by K.N. Casper

Leanna Cargill is from up North a damn yankee, as Southern folk say. But she's a steel magnolia if there ever was one and she's determined to succeed at her new investigative job down South. All the more since a nasty divorce has recently left her completely responsible for her little girl.
Jackson Fontaine may be a Southern gentleman, but he's also a wheeler-dealer businessman and as strong willed as they come. He's not about to let his sugar plantation and refinery go under he has a little girl to care for, too because of any operational irregularities Leanna Cargill may find.
Despite that, they like each other a lot. And when circumstances force Leanna to live at Bellefontaine, they both see how easily the four of them Leanna and Jackson and their two girls could make that arrangement a permanent one.