"Pandit Ka Dhabba" and "Sardar Ki Jalebi" ki Dukane in Old Gurgaon Market.
Not very hi-fi places to eat, but these are the historical places for eating in Gurgaon.
One is the "Pandit ka Dhabba" where they serve without asking, because they make just one dal and one subzi! Of course you can get curd, salad, Bisleri, etc. which they will gladly procure from the neighboring shops.
And then is the "Sardar ki Jalebi" right next to Dhabba, both of which are next to the Ram Lila Ground, near Post Office, in the Old Gurgaon Market. He serves nothing but Jalebi.