When it comes to food, there has never been another city quite like New York. The Big Apple--a telling nickname--is the city of 50,000 eateries, of fish wriggling in Chinatown baskets, huge pastrami sandwiches on rye, fizzy egg creams, and frosted black and whites. It is home to possibly the densest concentration of ethnic and regional food establishments in the world, from German and Jewish delis to Greek diners, Brazilian steakhouses, Puerto Rican...