December 4, 2014 6:27 AM EST

The British singer Charli XCX traffics in extremes. For Icona Pop’s global smash “I Love It,” which she wrote and sang on, she imagined crashing cars to spite an ex-lover. Then she bragged about trashing minibars and chandeliers in luxury hotels on “Fancy,” her No. 1 hit with Australian rapper Iggy Azalea. Now she’s riding the wave of her first Top 10 solo hit, “Boom Clap,” a song from the The Fault in Our Stars, in which she likens falling in love to being on drugs.

But despite how wild she sounds in her music, 22-year-old Charlotte Aitchison has been able to accomplish something rare for such a young artist. She’s won both the support of pop radio and the adulation of indie-music bloggers by steering her own career and rejecting anyone else’s vision but her own. She doesn’t want to destroy pop music–she wants to reform it.

“I can see pop music changing into something I can really run,” she says in the back of a van in Fort Lauderdale, Fla., ahead of her headlining show that evening. “There’s only a few more years left of the whole plastic, overproduced, bad-lyric, throwaway pop. It’s dying out because audiences are clever. Artists are running their own careers now, and that means it has to come from them. It has to come from their brain.”

The singer has always marched to the beat of her own drum machine. Young artists with mainstream ambitions don’t debut with an album of euphoric but left-field electro-pop (as she did on 2013’s critically acclaimed True Romance). They don’t give away massive hits to other artists (as she did with “I Love It”). And they certainly don’t retreat to Sweden to write a punk rock–inspired album that further eschews Top 40 conventions. But on Sucker, arriving Dec. 15, Charli swaps trunk-rattling bass lines and grimy synthesizers for crunchy guitars that are more snarling than sweet. If True Romance was the sugar rush of falling in love, Sucker is a middle finger covered in Sour Patch dust–a reinvention of her sound and a reaffirmation of all the counterintuitive career moves she’s made.

“I’m very judgmental of the music industry,” she says. Her style typically resembles all the Spice Girls rolled into one, but today she looks more like a hipster Elvira, with an untamed mane of near-black hair, a black slip dress and black boots. “That’s why I called it Sucker. It’s me pointing the finger and calling everyone a sucker, but at the same time, I’m aware that I’m part of that pop circus.”

Raised in England’s Hertfordshire County, Charli got her start posting recordings to Myspace and scoring invites to perform at illegal London raves, to which her parents happily provided transport. Those shows helped her build a buzz and land a record deal at age 16. Toward the end of recording True Romance, she wrote “I Love It.” Thinking it didn’t fit with the rest of her album, she let Swedish duo Icona Pop record it, even though her label had told her to keep it, saying she was sitting on a huge hit.

The label was right: the song’s boisterous “I don’t care!” hook sold more than 2 million copies in the U.S. and went to No. 1 in the U.K. But it has been wrong before. When Charli wrote “Fancy” with Azalea, she says her label “felt nothing.” The song later topped the Billboard Hot 100 chart for seven weeks.

The success of “I Love It” had its downsides. She and producer Patrik Berger were inundated with requests to write replicas for other artists. Feeling uninspired, she and Berger holed up in Stockholm and routinely worked till sunrise banging out dozens of two-minute punk songs to vent their frustrations. “We were both tired of the machine of pop music,” she says. “We just wanted to rebel against it.”

She eventually went back to writing pop songs–“She can write so much, she competes with her own material,” Berger says–but the punk sessions left a mark. Instead of showing off a newfound maturity, the feisty songs of Sucker revel in juvenile delinquency and testing limits. Charli says she and her label fought about True Romance, but now everyone’s on board with her vision. “I never get questioned on anything now,” she says.

She’s taking full advantage of that freedom as she plans her next album. It’s partly inspired by Japanese pop music, and she says it will sound like “another planet up in the clouds” and “intensely weird and childlike.” In other words, it’s yet another 180. “Just when people think they get it,” she warns, “I want to change it again.”

This appears in the December 15, 2014 issue of TIME.

Write to Nolan Feeney at nolan.feeney@time.com.

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