Consider the anchovy . That’s what Nick Perkins, a chef and the owner of Hart’s in the Bedford-Stuyvesant neighborhood of Brooklyn, would like you to do should you visit his restaurant and desire a burger. The only item on the menu that does not change with the season or the day of the week, it is a lamb patty served on a bun with fennel, aioli and an unusual optional upgrade: a row of marinated anchovies.

“We get a lot of people who are like, ‘Really? Is it really good?’” Mr. Perkins said. “And we always say, ‘We’ll buy your burger if you don’t like it.’ But it just never happens. People really like it.”

Mr. Perkins is allergic to dairy and always looking for foods to fill the cheese-shaped void in his heart. He found that tinned fish could act as a nondairy stand-in. “For me, learning about anchovies — my mom’s Italian, I spent a lot of time in Italy growing up — they do the exciting umami work that Parmesan does, for example,” he said.