The Thai chef Ian Kittichai recalls the early years he spent helping his mother stock up on ingredients for the family food cart. “I would wake up at 2.30 every morning,” he says.

Before becoming a “accidental chef,” Nikki Tran, an American who makes fish sauce, worked for a chip maker in the U.S.

We left Saigon in 1975 when I was only six years old and eventually made our way to California as a result of the Vietnam War. When I was a child, our diet consisted of dishes made by Vietnamese immigrants who were striving to preserve their native flavors. We were looking at ways to maintain …