Part of Sara Bareilles' charm is that she's one of the few millennial singer/songwriters who are unashamed of being polished and mainstream.

She revels in rich, detailed productions, which is what makes Once Upon Another Time -- a stopgap EP designed to tide over fans as she prepares her third album -- a little disarming at first.

Working with Ben Folds, a co-judge of hers from the NBC series The Sing-Off, Bareilles strips her sound to its core, opening the five-song EP with its skeletal title track.

Things get a little bit more elaborate from there -- "Lie to Me" is built upon trip-hop loops and swoons into Beatlesque psychedelia -- and she certainly demonstrates the influence of the perennially smirking Folds on the profanity-riddled "Sweet as Whole," a dirty joke that bogs down way too quickly.

Something similar could be said about the simplicity of the production: as sweet as some of these spare voice-and-piano tunes are, it's hard not to wish they were a little more adorned.

Nevertheless, the songs are generally good -- "Sweet as Whole" irritates like a piece of popcorn stuck in the teeth but the others are strongly constructed, melodic ballads, highlighted by the single "Stay" and "Lie to Me" -- and Bareilles remains a thoroughly engaging performer.

As a teaser, this certainly whets the appetite for her next full-length record.