Last June, Steve Ells, who founded Chipotle and launched the restaurant industry's fast-casual wave, carved out time for a vacation. The entrepreneur--who for years poured every waking hour into chopping, grilling, and packaging his burritos into what became a $20 billion company by the time he left in March 2020--headed for the Norwegian archipelago of Svalbard, roughly 800 miles south of the North Pole. Traveling by boat from there, he made daily, five-hour outings, hiking up and skiing down a series of peaks.

No part of his trip sounds relaxing to me. As we walk uptown through Manhattan's clogged streets on a brisk and bright winter afternoon, the endlessly energetic, 57-year-old Ells recounts how he climbed each peak with a pounding heart, peeling off clothing layers and stuffing them into his backpack as he went. On the way down, Ells--a Colorado native and experienced skier--navigated snow conditions that varied, he says, "from the texture of mashed potatoes to ice to smooth-capped surface to rock."

As Ells arrives at the front door of Kernel, his new, plant-based restaurant on Park Avenue, surrounded by office towers stocked with hungry workers, he argues that what he's doing now makes ski trekking in the Arctic seem like a day at the beach. Four years ago, Ells left the company he proudly founded, a crushing conclusion to an episode marked by a series of food borne-illness outbreaks and critiques about the treatment of workers. That led him to do a lot of thinking about his next act. Inspired by Bill Gates's book How to Avoid a Climate Disaster, Ells decided to focus on serving sustainably sourced, healthy food. He spent $10 million of his own burrito bucks developing his latest venture, which opened in February.

In some ways, Chipotle and Kernel are siblings. Kernel charges about the same as Chipotle: A plant-based burger and side costs about $12. The first Kernel location is even the same size--about 1,000 square feet--as the first Chipotle Ells opened in 1993 in his hometown of Denver. Ells seems to want to follow an aggressive expansion plan by opening nearly a dozen restaurants in Manhattan over the next two years. He wants to reshape the fast-casual market he helped create with Chipotle, which today has more than 3,300 restaurants and a recent market cap of more than $65 billion.

But the differences between Chipotle and Kernel clearly show that Ells is an entrepreneur on a quest for redemption. This time, instead of surrounding himself with fellow culinary school-trained chefs, Ells has hired a Harvard MBA with McKinsey and investment banking chops as president. He also speaks often about his efforts to improve food handling safety, namely by establishing a central kitchen where chefs prepare fresh ingredients all day that are then delivered by bike to nearby restaurants.