If I were to pick a single Indian aka desi food, my vote would go to the Amritsari Kulcha with Chole Masala and that is specific to the ones I tasted in the city of Amritsar. I know almost every city in India serves Amritsari Kulcha but the authentic ones and the best are those found in Amritsar only.
The Kulcha is a kind of bread made with refined white flour and is then leavened and has a coat of butter with a hint of garlic applied on it. It has even got a stuffing inside the bread. It pairs very well with a spicy dish of chole masala. That's the main thing about Chole-Kulche, but in Amritsar, you also get a dip with raw onions and green chillies in some kind of a spicy water.
The best thing about Amritsar is that food here is so affordable and the restaurants in Heritage Street that leads to the Golden Temple remain open 24 hours a day! A thali with Chole and Amritsari Kulcha costs only 99 rupees! Every night for dinner, I used to have this along with a glass of thick malai lassi! The combination is just superb and I have absolutely no words to describe how great the taste was! The soft kulcha and the tangy dip along with the spicy chole masala and to cool everything down, you can take a sip of the lassi. Damn! I can feel that taste lingering on the edge of my tongue right now. You really have to try this to find out!