Seriously doubt Cassandra Wilson refers to herself that way but Cassandre McKinley might. Mellow-sounding, not adventurous, solid results in delivering a lyric. Her Site: Slim Discog; nothing since '06 (but it was killer):

Some tunes: << A Marvin Gaye classic, re-imagined so well << Just lovely--empathic surroundings, those guitar tones on the keys especially. <<Classic singer-with-Big-Band sound--I just love it. << Great sax solo. <<Terrif in less-formal surroundings