A few years ago, Tegan and Sara made a bold decision: They became a full-on pop group. After more than a decade of making indie-rock hits, the Canadian twin sisters largely traded guitars for synthesizers, focused on hooks and became even more of a success. Their 2013 album, Heartthrob, subsequently made it to Number Three on the Billboard 200 and the single “Closer” topped the dance chart in the U.S. Then, the next year, they anted up and recorded the family-friendly pop explosion “Everything Is Awesome!!!” with the Lonely Island for The Lego Movie and earned themselves an Oscar nomination in the process.

But for all of the ways they refigured their sound, the biggest lesson they learned was simplification. Earlier this year, Sara Quin told Rolling Stone that after working with several producers and songwriters – including Jack Antonoff, Rob Cavallo and Mike Elizondo, among others – they realized they had invited too many cooks into the kitchen.

For the duo’s new LP, Love You to Death, the sisters worked only with producer Greg Kurstin, whose credits include Sia and Adele and who worked on the lion’s share of Heartthrob. Together, the Quins and Kurstin crafted strong, thoughtful, catchy songs like “Boyfriend,” “100x” and “U-Turn,” all of which explore various forms of relationships, from romantic ones to their own sibling dynamic. Here, Sara tells Rolling Stone how taking risks has strengthened the duo both as songwriters and as sisters.

What would you have done if Heartthrob tanked?
I don’t know what we would have done. I don’t think we would have said, “I guess we have to get the old electric guitars out again and write more indie-rock songs.”

You worked solely with producer Greg Kurstin, who worked with you on Heartthrob, on this one. What did he bring to the album?
Tegan and I work best with producers who work almost like editors. We put a lot of work into our demos. Some of them may already have 60 tracks [of instruments] on a song. We really need someone who can dig through all of that and pick the strongest parts and elevate them. He might ask us to play something in a different key or faster. Greg helps us workshop our ideas.

Your first single is “Boyfriend.” How did he help you with that one?
When I brought that one in, I thought it would be scrapped. When he stripped back the demo, I realized it had a really strong arrangement and a strong melody, and the lyrics were great. Like, holy shit – this could be a single. It might have been on the cutting block otherwise.