Laura Benanti's American Songbook Night at the Allen Room When Laura Benanti was born in New York City in 1979, she emerged from the womb covered in sawdust and pancake makeup, squalling "There's No Business Like Show Business." That's a metaphor, of course, for the sensibility of this rising star who won a Tony Award for her portrayal of Louise in the recent Broadway revival of "Gypsy." This Broadway baby may be 32, but on Saturday evening at the Allen Room she conveyed the breathless, starry-eyed enthusiasm of a teenager carried away by having just won the lead in the high school musical and entering "Glee" heaven. Laura Benanti performed at the Allen Room at Lincoln Center as part of the American Songbook series. For a good part of her concert, the final event of this season's American Songbook series at Lincoln Center, Ms. Benanti, accompanied on piano by Mary-Mitchell Campbell, strutted her considerable charm as a comic goofball. The centerpiece of the show was a medley of fragments of favorite songs that ran from "Bad Romance" and "Fame" to a Bob Dylan imitation and an operetta-style version of "And I Am Telling You I'm Not Going." Although parts of this medley were clever and funny, it felt more like a disorganized sketch than a fully fleshed concept. The foundation of Ms. Benanti's talent is a limber soprano whose power and innate expressiveness she unleashed with a casual authority that was almost startling. Especially at the top end, where theatrical voices tend to thin, Ms. Benanti's tone spread out and acquired more colors in somewhat the same way that Audra McDonald's upper register can enlarge notes and emotions. She fully inhabited Jason Robert Brown's scalding ballad "Still Hurting," from the musical "The Last Five Years," which first opened in Chicago in 2001. She maintained a confident balance between art song and pop while singing Jeff Blumenkrantz's setting of the Edna St. Vincent Millay sonnet "Love Is Not All." Although she emphasized the strength of the music rather than the words - more interpretive liberties would have been welcome - the sound of her voice was glorious.