World-renowned chefs are gathering to cook up fancy meals made from an unconventional ingredient: food waste.

Chef Dan Barber, owner of Blue Hill restaurant in New York, is launching a pop-up restaurant called wastED. From Feb. 24 to April 2, on the roof of Selfridges department store in London, the pop-up will serve meals made by a range of guest chefs, including Michelin-starred Gordon Ramsay, reports Bloomberg News.

All of the meals will be made from “food waste” collected from local producers. That includes things like bruised vegetables that would usually be discarded, according to Eater.com, and leftover pulp sourced from beet farms, reports The Guardian.

“I am in favor of expanding the definition of what is waste food,” Barber told Bloomberg.

“What we are doing is a new way of looking at farming,” he added. “Eating the entirety of the farm in the same way that we have nose-to-tail eating of the animal.”

You can make reservations for the pop-up online. But fair warning: You won’t know which guest chef you’ll have on any given day.

GERRY PENNY via Getty Images British Chef Gordon Ramsey stands at the entrance to his Chelsea restaurant in London in January 2001, after being awarded three Michelin stars.

One significant contributor to food waste is the discarding of “ugly” produce ― or fruits and vegetables that get tossed by producers, vendors and consumers alike for being blemished, misshapen or not meeting cosmetic standards.

Barber’s London pop-up is his second wastED event seeking to incorporate food waste into high-end meals. The first one, held in March 2015 at Blue Hill, featured famous chefs like Mario Batali serving up odds and ends of vegetables and “ugly" produce, like bruised sweet potatoes.

“A project like the one I am trying to do at Selfridges couldn’t have existed even 100 years ago,” Barber told The Guardian. “Because there was no waste from agriculture, everything was utilized.”