Möllevångstorget and the side streets around the square are full of Middle East, East Asian and other supermarkets where you can find all the interesting food not found in your average Swedish supermarket (although they too are more interesting these days). The square itself also hosts a market Tuesday-Saturday where you find cheap fruit and veg and other picnic food.
Favorite Dish: I go here to get spices for our curries :-)))
This isn't one restaurant. It's an area full of restaurants. You can find greek food, Iranian food, Chineese food, Thai food, ...
A good idea is to walk around the streets surrounding the square. There are a lot of restaurants in the nearby streets.