Headlong Dance Theater’s Andrew Simonet, Amy Smith and David Brick were sweeping up onion husks after a recent rehearsal in their South Philly studio. Now in their 20th year of creating a distinct hybrid of dance-theater, the performers are still cleaning up their own messes.

Their latest creation, “Desire” — one that calls for a stage covered in onions — marks the first time in more than a decade that HDT has performed with their original three-person lineup.

The piece borrows heavily from Richard Brautigan’s 1968 novel “In Watermelon Sugar,” a chronicle of the rise and fall of a utopian community. But “Desire” is an examination of a more contemporary idealistic group: Headlong Dance Theater itself.

“I think what we’re struggling with here is: Can you make a little utopian micro-world in your dance company — or your rock band?” says Simonet, sitting on a freshly swept stage. “‘Watermelon Sugar’ is about doing that, but it’s also about how bristle-y and prickly it is to do. It’s not just a sunshiney, happy LSD trip.”

Directed by Swarthmore professor K. Elizabeth Stevens, “Desire” will feature old R.E.M. tunes from the troupe’s college record collection.

As for all those onions onstage? “We like the idea that they’re sweet when they’re cooked, but real pungent — almost too much — when they’re raw,” says Brick.

But then Simonet attempts to peel the metaphor a bit further: “For me, the really interesting stuff in relationships happens a long time into it. I used to think that all the really interesting stuff happens at the beginning — the fiery, cool s–. But now I feel like the good stuff is after 15, 20 years.”