For the salad, wash the potatoes, cook for 20 minutes, rinse with cold water and peel. Leave to cool a little. Clean, wash and halve the radishes. Wash cucumber, cut into slices. Wash chives, cut into fine rolls.
Clean, wash and pluck the frisée into bite-sized pieces. Cut potatoes into slices. Mix the salad ingredients. Peel and chop onion. Boil up vinegar, add diced onion. Season with salt, pepper and sugar and pour hot over the salad.
Leave covered to draw. Meanwhile clean and wash the plaice, cut open along the middle bone and remove some of the fishbone. Sprinkle the plaice with lemon juice and salt. For the filling, wash and chop the dill.
Clean and wash the spring onion and cut into thin rings. Mix dill, spring onions, crabs, lemon peel and egg yolk. Season with salt and pepper and fill into the plaice. Turn the fish carefully in flour.
Fry the plaice in two coated pans in hot oil for about 5 minutes on each side. Serve the plaice and salad garnished with lemon wheels and dill.