Before day one of their road trip ends, Mark and Scott make room for one more crazy pizza concoction. For their final slice of the day, Scott and Mark make a stop in Scott’s native New Jersey to visit the oldest family owned pizzeria in the United States, Papa’s Tomato Pie. Established in 1912, their mustard pie is a local favorite, made with a thin layer of mustard between the crust, cheese, and tomato sauce. Will this mustard pie pass Mark’s pizza test? Whose idea was it to put mustard on a pizza in the first place? And where are Scott and Mark going to sleep tonight?

What makes a pizza, a pizza? Lucali owner and old-school Brooklyn pizzaiolo Mark Iacono has a strict pizza formula: sauce, cheese, and dough. That’s it. But renowned pizza enthusiast Scott Wiener believes that the beauty of the slice comes from its creative customizability; even if it’s topped with cheeseburgers or constructed with paella. Scott travels all over America to spotlight the country’s most unique pies and make a case for whether these new customizations can, in fact, still be considered a pizza. This time, he’s taking Mark along for the ride on an East Coast road trip to try the craziest concoctions claiming to be pizza... but are they really dough? This video "Mustard Pizza: Can Mustard Replace Tomato Sauce? ", first appeared on http://thrillist.com.