When Mr. Onwuachi opened the Shaw Bijou in 2016, backed by two investors who had approached him, he centered the menu on his life story, which he had carefully honed years earlier while he was trying to win the sympathy of his subway customers, or to become a fan favorite on “Top Chef.”

The tasting courses were so tightly focused on that story that they included a Butterfinger mignardise , a small pastry inspired by the best-selling item from his days hawking candy, and a fisherman’s pie, the dish his mother used to make for him on his birthday, gussied up with charcoal-roasted madai and lobster foam.

Mr. Onwuachi charged $185 for the experience, and in interviews proclaimed that the 32-seat restaurant, one of the city’s most expensive, would also be its best. The food press zealously covered the run-up to the opening, even though the highest-level restaurant job Mr. Onwuachi had held before this was as line cook.

He had begun writing his memoir. “I thought it was going to end with me opening the Shaw Bijou and getting three Michelin stars — like, this is it!” he said.

But after all the hype, his fortunes tumbled: The restaurant ran out of money, Mr. Onwuachi clashed with his investors and The Washington Post published a negative review that drew nearly 500 comments. “Honestly, though, a real Butterfinger is better than the chocolate-robed salt lick served here,” the review said.

Mr. Onwuachi says he had become too caught up in his own vision. “I think about what if I had asked more questions, if I were more experienced in business, if I had asked about the budget in the beginning,” he said. “We were on our way to making strides. But instead of asking the right questions, I was excited in the moment.”

The investors closed the restaurant, and Mr. Onwuachi considered leaving the city. “I was 26 and experiencing this very public shaming,” he said, an ordeal that he still recalls with some anguish.