In a review in The NY Times it says that Esmeralda Santiago’s “Conquistadora” is a novel about a Puerto Rican plantation mistress. It’s set in mid-19th-century Puerto Rico. Puerto Rico was one of the last holdouts for slavery in the Americas, ending it in 1873, although slavery in Cuba wasn’t abolished until 1884. The novel’s heroine ends up a widow running a sugar plantation who becomes romantically involved with an overseer. She is a heroine, however, of mixed reviews: she was not above having her slaves tied to a tree and whipped when it profited her.
http://www.nytimes.com/2011/07/17/books/review/book-review-conquistadora-by-esmeralda-santiago.html