Rinse the potatoes and cook in salted water for about 20 minutes. Drain, peel, cut into slices.
Clean spring onions, rinse, divide into rings. Mix everything with the onion.
For the dressing, heat clear soup, season with mustard, salt and pepper. Pour over the lettuce. Drizzle vinegar and oil over it. Dress the lettuce.
In the meantime, rinse fish fillets, dry and perhaps cut in half. Sprinkle with juice of one lemon, season with salt and season with pepper. Turn first in flour to the other side, then through the beaten eggs and finally turn in breadcrumbs to the other side. Fry in heated clarified butter on both sides for about 4 min until golden brown.
Serve the potato salad with the fried fish. Garnish with parsley and lemon if desired.
By the way: Did you know that clarified butter is obtained by extracting water, milk protein and lactose from butter?