Barbara Sfraga's only disc so far, 1998's Oh, What a Thrill (Naxos), is a remarkable display of versatility. Her slow-dance simmer on "Great Balls of Fire" pegs her as a neatly updated throwback to old-time torch singers and blues-belting mamas, and her warm, round contralto projects an earthy, enveloping sexuality on Rodgers and Hart's "I Didn't Know What Time It Was." But when she dances through her own words to Lee Morgan's curvy hard-bop classic "Free Wheelin'" (retitled "Livin' the Life of Freedom"), or picks her way through the tongue-twisting lyrics to "Slug It Up," Sfraga becomes a thoroughly modern jazz singer, an heiress to past vocalese champs like Annie Ross. Maybe the roundabout route she took to jazz helped develop her stylistic range. Starting out as a church organist, she turned to classical singing (the source of her terrific intonation); in college, Sfraga was seduced by the recordings of Ella Fitzgerald, Sarah Vaughan, Anita O'Day, and Mark Murphy. That broad list of influences accounts for Sfraga's much appreciated refusal to decide what kind of singer she wants to be when she grows up. She's in town to record her second album (with Chicago producer Mark Ruffin), but she'll tone up for the studio with a series of gigs, all with guitarist John McLean and bassist Marlene Rosenberg. Friday, September 27, 9 PM, Pops for Champagne, 2934 N. Sheffield; 773-472-1000. Saturday, September 28, 8:30 PM, Pops Highwood, 214 Green Bay, Highwood; 847-266-1313. Sunday, September 29, 8 PM, Green Dolphin Street, 2200 N. Ashland; 773-395-0066. Wednesday, October 2, 8 PM, HotHouse, 31 E. Balbo; 312-362-9707.