Happy Tummy is a tiny eatery located in the Karkardooma Community Centre and is actually quite popular among the East Delhi folks. The community centre is just 300 meters from the metro station, so you can just walk your way to this eatery.
Happy Tummy opens at around 12pm and stays open till about 1am. It is the kind of place you go to when you are in the mood to eat a carb-loaded Chinjabi meal or are having midnight cravings. The average price for two is INR 1K.
Their menu includes sizzlers, rolls, pizzas, pastas, burgers, sandwiches and French fries. They also have Chinese options (or Chinjabi) like momo, chili potato, spring rolls, noodles and rice. If you want to stick to good ol' North Indian comfort food, dal makhani, different paneer gravies, mix veg and potato sabzi are some of the other things that you can find on their menu.
You can also choose to cool off with their variety of shakes and coolers.