If you are unable to find any quinces you can use pickled apples or plums. They will taste slightly different, but are also good. I smoke the fish in a small ABU smoker. You can also smoke the fish in a fireplace, or use pre-smoked fish. (This also works with mackerel.)
Place the fish in an ABU smoker, add wood chips, light and allow it to smoke for 10 to 15 minutes until the fish is ready. It should be cooked well enough so that the meat easily falls away from the bones.
Mix together the sour cream, onions and chives.
Serve the fish with the sour cream mixture, the blue cheese and the pickled quinces.