Peel and finely chop the onion. Peel, wash and finely grate the potatoes. Mix potatoes, egg, flour, onion, salt and pepper well. Heat the oil in a coated pan and bake about 12 potato pancakes in portions, turning. Drain on kitchen paper. Add one teaspoon of sour cream to each pan.
Cut the fish a little bit smaller. Cut lemon into small slices. Put trout and cranberries on one half of the buffers. Cover the other half with salmon, lemon and dill. Arrange on plates, garnish with lemon slices, lettuce and tomato wedges