Some of the hidden gems are:
•De-jag's ice cream parlor-Rajouri garden
•Sardar ji malai Chaap-Subhash nagar
•Darshan chole bhature-Subhash nagar
•Monika cafe for chole bhature , the best-Vikaspuri
•you can also explore Rajouri Garden main market for ethnic wear and western too
•Atul chaat corner-Rajouri garden
Explore Tilak Nagar streets, there's something on every street, it's called the mini Punjab of Delhi, due to the majority punjabi population, small to big food joints are there, offering really good food.