Only in New York could an Italian-American mayor find a piece of the minuscule mountain village his family left a century ago just steps from City Hall.

Mayor de Blasio frequently grabs lunch at Pisillo Italian Panini shop on Nassau St. , which Antonella Silvio opened in November 2012 — the same month de Blasio was elected mayor.

She took that as a good sign.

“I said, ‘I think this — it is my destiny,’ ” said Silvio, who co-owns the shop with her husband, Carmelo Nazzaro .

Silvio knew de Blasio’s grandfather Giovanni de Blasio was from her hometown, Sant’Agata dei Goti — everyone there knows who the mayor is — but he didn’t know her.

So her family told the mayor’s distant cousin Roberta Mongillo, who they knew well. Mongillo quickly informed de Blasio that there was a hometown cook within walking distance of City Hall.

Shortly after he was inaugurated, the mayor came by to say hello and sample the paninis, which are served cold on freshly baked bread.

“It was so nice,” said Silvio. “He wished me good luck.”

Since then, de Blasio has become a regular, with his staff stopping by several times a week to pick up his food.

His typical choice is something he concocted — prosciutto, porchetta, bufala mozzarella, roasted peppers, arugula and balsamic dressing. It’s now on the menu, dubbed the “Sant’Agata.” Top aides also frequent the shop, which is decorated with framed prints of Italian scenery, a Juventus soccer team banner and a picture of Silvio and de Blasio.

Silvio, who lives with her husband and two kids in Bensonhurst, Brooklyn, said she opened the restaurant because she couldn’t find an authentic Italian sandwich shop she liked.

“I always said to my husband, what kind of sandwich do they eat here?” she said.

Many of their ingredients are imported from Italy — conveniently, as Silvio’s husband also runs an import-export business .

New Yorkers seem to appreciate the Italian touch. The shop had a 41/2-star Yelp rating Friday from 127 reviews.

And perhaps more important for de Blasio, it also has an “A” rating from the city Health Department.

Silvio said she and her husband left Italy eight years ago because they struggled to find work.

“New York, they give a chance for everybody,” she said. “It’s a beautiful country.”