“Little India” began on East 6th Street (between First and Second Avenues) in Manhattan in 1968, when the first Indian restaurant opened. By at least the 1990s, a joke has frequently been told that all of the many Indian restaurants on the block “share the same kitchen.”
 
 
Google Books
O Solo Homo:
The new queer performance
By Holly Hughes and David Roman
New York, NY: Grove Press
1998
Pg. 62:
On my way to John’s apartment in the East VIllage, I walked down East Sixth between First and Second. This is the block with all the Indian restaurants. Shagorika. Kismoth. Taste of India. Passage to India. The Gastronome Ghandi. Ghandi to Go. They’re all there! I used to imagine that all these restaurants shared the same kitchen. I was sure there were block-long conveyor belts delivering huge piles of poori and papadam like stacks of laundry to each small restaurant.
       
The Best - Chowhound
Best Indian Restaurant on East 6th Street
There’s a popular joke/rumor that the food in the Indian restaurants on East 6th Street are all cooked in the same kitchen. Seriously, which restaurant on East 6th Street serves the best food?
Ruby Jan 24, 2001 11:54AM
 
Yale Daily News
The preaching of hate to the already converted
Jim Sleeper
Published Wednesday, April 23, 2003
(...)
As they dragged my name from Frontpage to the Weekly Standard to MSNBC and beyond, I thought of a little block on Manhattan’s East 6th Street with five Indian restaurants. The joke is that they all have the same kitchen.
   
East Sixth Street Indian - Manhattan - Chowhound
The Chowhound consensus seems to be that they all suck. I disagree. I have been going to Rose of India for 15 years and enjoy it every time. Also Haveli, on 2nd Ave. right off 6th St. As for the “one kitchen” thing, that is a very old joke based on the high concentration of restaurants with similar—if not identical—menus on that block.
neighbor Dec 03, 2004 11:53AM
(...)
Yes, the large underground kitchen is true. You know all the smoke coming out of the streets of Manhattan? Yup, that’s all from the 6th Street Underground Kitchen. All the Indian restaurants are connected through a complex underground tunnel system.
 
The reason why the title of “Best Indian” transfers from one place to another every year is because of the annual auction. The top three bidders get the best from the underground kitchen. The others get the leftovers and the stuff that falls on the ground during transport in the tunnels.
 
It’s all true. Serious.
Johnny S Dec 03, 2004 05:09PM
 
Google Books
Traveling Solo:
Advice and ideas for more than 250 great vacations 
By Eleanor Berman
Guilford, CT: Insider’s Guide
2005
Pg. 255:
“Little India” covering all of 6th Street between First and Second Avenues, and spilling over onto First Avenue, is lined with tiny Indian restaurants, most BYOB. THere are at least a dozen to try.

at 334 East 6th Street gets good reviews—or just pick the decor that pleases you; some people joke that they all use the same kitchen, anyway.
 
Manhattan - Chowhound
6th street Indian
is it true that there is one kitchen cooking for all the restaurants?
or can you offer any favs?
thanx gt
gtmajors Nov 20, 2006 05:08AM
 
Such an old joke that they all share the same kitchen. Some of them are allied with others, but they are all different kitchens. This topic is a well discussed one on the boards. Favorites on the block are Banjara (corner of E. 6th and 1st Ave) and Brick Lane (E. 6th closer to 2nd). You should be able to do a search.
Non Cognomina Nov 20, 2006 06:54AM