I discovered this place the first week I arrived in Oslo. And seriously, it is food heaven!
The building is filled of little “stands” offering all sorts of food: thaï, italian, cheese & wine, pastries, seafood, …
I personally went to “Noodles”, an asian street food stand which serves woks you can design by yourself! It was really tasty, but I had some difficulties finishing my plate (and I never do, so you must be very very hungry!)
On your way out, you can even grab an ice-cream, as the little shop on the left corner seemed very popular (despite the cold weather brrr).