Singing mostly obscure works by Bernstein, Sondheim, Weill and the lesser-known Marc Blitzstein, her soprano conveys a freshness that is closer to cabaret than Bizet. But rather than burying her operatic roots, Upshaw uses her classical skills – impeccable phrasing and controlled vocal power – to establish character and emotion. She does best with two Kurt Weill songs from “Lady in the Dark” – the lilting “The Saga of Jenny” and “My Ship,” in which her dreamy voice actually begins to sound like the wind in the song’s silky sails. Even in Bernstein’s potentially mawkish “I Feel Pretty,” accompanied by two pianos, Upshaw marries the simple with the lush, the youthful and ageless. Despite acclaim singing music from Mozart to Gorecki, Upshaw talked recently about a career singing commercial jingles. She could probably pull that off, too.