Brandi Carlile likes to break out the Boy Scout shirt she wore on her self-titled debut album in 2005 whenever she takes the stage at “old-time rock clubs” like Fort Lauderdale’s Culture Room, which she played Thursday night.

Were it any other singer/songwriter who launched her music career in Seattle and echoed such a sentiment, the sight of the Troop 575 patch on her left sleeve might hint at an evening of down-and-dirty grunge. Instead, Carlile’s powerful acoustic set proved less an ode to the Culture Room than it was a nod to the Grand Ole Opry.

For anyone familiar with the 30-year-old’s journey, this should come as no surprise. She was raised in Washington state, at a time when Nirvana and Pearl Jam were putting Seattle on the rock map, by a mom who also was a country singer. Though Carlile would later find inspiration in the likes of Elton John, Queen and Radiohead (her cover of “Creep” is a must-iTunes download), she was equally influenced by the hardscrabble lyrics and heart-wrenching sounds of Johnny Cash and Patsy Cline.

Even with her full band, Carlile always has been a little-bit-country-little-bit-rock-n-roll kind of performer. But flanked only by “the twins”—twin brothers Tim and Phil Hanseroth—her country side permeated an evening of stripped-bare standards from her back catalog (“Dreams,” “Turpentine,” “Pride and Joy”), songs from her forthcoming new album (set for a May release), and, yes, some Nashville classics.

Early in her career, Carlile admittedly fought the twang that comes so naturally to her. But it was clear in the way she wrapped herself around songs like Tammy Wynette’s “Stand by Your Man” and the show-closing “Crazy,” by Patsy Cline, that she fully embraces a vocal range that can only be described as jaw-dropping.

The Culture Room, one of my all-time favorite concert venues, offered the perfect coffee-house backdrop to display that voice. “If you put up with a couple of ballads,” Carlile told the crowd, “I promise to rock your face off.” In this era of “The Voice” and “American Idol,” consider how few vocalists really have enough command to channel their inner Jeff Buckley and Janis Joplin—sometimes in the same song. On Thursday, Carlile brought a hush over the packed room with soulful turns, like “Promise to Keep” off the new album. Later, she brought the house down with a bawdy version of “The Story,” her 2007 song that was used in several commercials and helped to put Carlile on the map. (Check out the original video on YouTube.)

Carlile promises a return to South Florida—hopefully at the Culture Room—with her full band as they plan a fall tour. Catch her if you can, and check out other upcoming shows at the Culture Room.