He ordered the exasperated waiters to move a heavy credenza and set up an extra table by the front door. He supplied me with a yarmulke and an entirely Hebrew Haggadah. Illiterate in the language, I pretended to read it as I sat there alone, between the wall and a display case of macaroons, looking at medieval illustrations of the 10 plagues.

Everyone seemed to know one another. Many biceps were squeezed. Many cheeks were kissed. Adults bathed with attention Daniel and Aaron, the only small children in the place as far as I could tell. (The Italian birthrate is a paltry 1.4 children per family.) An older woman walking by me worried out loud in universal Jewish mother fashion that I was too close to the door and would “catch pneumonia.”

The proceedings began at 9:05 p.m., with Seder plates and baskets of matzo on each table. A waiter asked if I wanted wine, but I asked for grape juice because, having entirely dropped the ball on Dryuary, I was observing Drapril. The waiters, clearly not well-versed in Jewish customs, huddled over this insane request for succo d’uva by someone older than six and sheepishly asked Mr. Ouazana if the restaurant carried any. “Of course we do,” he told them.

It wasn’t Kedem, or even — gasp — Welch’s, but something called Nes did the job. The juice wasn’t the only change on the table for an Ashkenazi New Yorker far (like Trappist-1 far) from orthodoxy and keeping kosher and Italian traditions. “In Rome, everything is different,” Mr. Ouazana said.