Well, Mathias loves soups and especially fish soups, so I am somehow not surprised that he stumbled upon this dish which we only later learned is one of Cambodian national dishes :). He had it at a small local street stall though and I think it was a slightly different version (or maybe there are many) compared to the recipe I found. Mathias had Samlor Korko with sour- mango taste. He absolutely loved it!
So here is a recipe I found on the web for this national dish, even though as mentioned it is a slightly different version then the one Mathias had.
http://www.cambodia-picturetour.com/samlor-korko-khmer-fish-soup-with-vegetables/