Easy. Joni Mitchell. Proof: her exquisite, mature, 2 CD Travelogue album (2002). Highly recommended jazzy soundscapes.
Nuanced voice. Pleasant to listen to. A truly jazzy interpreter-performer-songwriter.
Further: Top female folksinger-songwriter of all time. Biggest catalogue of original material. First significant, original folk-guitar-tunings of all time. The most poetic female folksong-writer of all time. First female singer to illustrate her own albums with her own paintings (see above album cover). A multi-media artist as well. Mitchell was the first significant female singer Canada ever produced. One of the top recording artists and performers of the ’60s, ’70s, and ’80s.