Here's what a pav bhaji is, most often: two almost-sweet buns of vague Portuguese influence that bear an uncanny resemblance to Martin's potato rolls. Usually the bread has been toasted slightly in salty butter. The filling is a mix of vegetables like potatoes and onions that have been cooked down with tomatoes and spices, and more often than not, these components are served separately, so the particulars of stuffing are left up to the eater.

The snack's origins trace back to Mumbai's textile mill workers in the 19th century who needed something filling, served quickly. Roughly 164 years later, pav bhajis still get the job done, and fast. Granted, this concept comes up short on nutritional value, but as an assembled work of art, a pav bhaji is basically the most delicious mashed potato sandwich on bread. Who could argue with that? For whatever reason, though, the idea has yet to catch on in New York.

So it's salty buttered carbs stuffed with carbs and onions?

Sounds like a knish.

Pav bhaji is two pieces of bread served with a simple lentil spread. Apparently, the particular type of bread used in pav bhaji is only produced in Gujarat, so restaurants in America have resorted to using buttered hamburger buns.  http://www.laweekly.com/squidink/2014/08/28/las-best-indian-food-has-no-meat?showFullText=true

Next up was the Pav Bhaji Fondue (Rs 395). The bhaji is served in a fondue pot garnished with chopped onions along with mini buns and fondue forks. We dipped our buns in the bhaji and were transported to another world. The aerated frothy bhaji tasted as good as the one you would get at your favourite pav bhaji corner, yet, was light on the stomach. - See more at: http://www.mid-day.com/articles/molecular-magic/15519193

This one is salty buttered carbs that you dip into carbs. Yum!