Thankful was released in the immediate wake of Kelly Clarkson’s winning run on American Idol, and though her debut finds her still shedding some of the trappings of the show and formulating her own identity, it puts primary focus on the most crucial element of Clarkson’s presentation: her voice. Full-bodied but remarkably flexible, Clarkson’s vocals have just enough attitude to connect her to classic soul singers like Gladys Knight without blatantly aping their style. “Miss Independent,” “The Trouble With Love Is,” and “What’s Up Lonely” are reminiscent of Christina Aguilera’s music, but while the two singers share the same urgent attitude, Clarkson avoids the histrionics that sometimes take Aguilera’s performances over the top. The low-key, shuffling soul of “Thankful” shows Clarkson’s ability to ground a track even as she’s pushing it forward with her energy. Thankful was executive-produced by Clive Davis, who guided the careers of Whitney Houston and Alicia Keys. He knows exactly how to maximize the talent of a top vocalist, and Clarkson’s debut is a fine introduction to one of modern pop’s most commanding singers.