Heat the butter in a frying pan, add the chopped leeks, three tablespoons water, cover and cook for 10 minutes until soft. Add cream cheese, mix and put salt and pepper.
In the middle of pastry put a salmos fillet and half mixture of leek and cheese. Bring all four ends of the pastry in the center in order to create a package. Put some butter on top and bake the packages in a slightly greased pan at 200 ° C for 25 minutes, or until they turn golden brown.