As with most cuisines from far away countries, an infallible way to learn what restaurant represents the most authentic local dishes is to ask someone originally from there where they go to eat when they crave food from home. Ask anyone originating from India where they like to go eat their local cuisine in Barcelona and they will probably tell you about Bembi.
I especially like this place because not only is the food amazingly good, but it’s also very exotically decorated, after a meal there you feel like you went on a little trip and visited their incredible land. I usually go to Bembi if I’m in the neighborhood during lunch hours, as they serve an amazing lunch menu with their a-la-carte staple dishes for € 15 per person. Dinner is great too though, as you can then enjoy the great atmosphere of the place even more.
If you’re looking for good Indian food in Barcelona, this is the place to go!