The inspiration for Ian MacAllen’s book came to him one night several years ago over a plate of veal Parmesan at the now-closed West Village restaurant Trattoria Spaghetto. “I knew they would look strangely at you if you ordered that in Italy,” says MacAllen, who has Italian ancestry.

“But [veal Parmesan] was such a different food from what my wife and I had had when we were in Italy. I started Googling things about the origins of Italian-American food, and it didn’t have any good answers. From there, it spiraled out of control. Before I knew it, I was writing a book.”