New Schools Chancellor Richard Carranza didn’t have to chow down on a school lunch Monday, his first day on the job.

The new schools boss broke bread instead with Mayor de Blasio and his wife, Chirlane McCray, at legendary Katz’s Deli on the Lower East Side, where they ordered a pastrami sandwich, matzo ball soup and Cel-Ray sodas.

The sandwich came with a tourist price tag: $21.45 before tax and tip. But aides said the mayor picked up the tab.

De Blasio has dined before at the deli, including in October with Vermont Sen. Bernie Sanders.

The walls of the eatery are packed with photos of a range of celebrities and politicians — from actor Dom DeLuise to Comptroller Scott Stringer — but a shot of Hizzoner was nowhere to be found.

A rep for the deli said the mayor’s photo had been hanging on a wall but was damaged and is being repaired.

Carranza, a former superintendent in Houston and San Francisco whose salary is $345,000, is easing into his gig running the city’s 1.1-million-student public-school system by starting during a vacation week.