OH!
DR edisaurus - It sounds like you had a "Mozzarepa" at the street fair. They're a "Italian-Americanization" of a Venezuelan food. An
arepa is a corn meal patty made from
masa harina. It basically acts as a bread, and then you can fill it with whatever you like. I had a Venezuelan housemate when I was in college, and we would sometimes throw Arepa Parties. We would make mini ones, and then put out a whole spread of various fillings: cheeses, roast pork, vegetables, etc.
The next time you're in NYC, you should try to make your way down to the East Village and check out
Caracas Arepa Bar for the real stuff. Their
de Pabellon (shredded beef, black beans, sweet plantains and aged cheese) is sooo good.
*They also have great empanadas too, and their housemade hot sauce is one the best and unique in the city, imho.