Peel 4 onions and cut into rings. Boil 1/2 litre water, vinegar, 1 1/2 teaspoon salt, sugar, bay leaves, mustard and peppercorns in a pot. Simmer for about 5 minutes, add onion rings and simmer for another 2-3 minutes. Let the stock cool down. Wash herrings thoroughly and drain. Put the flour on a plate.
Salt herrings inside and outside, turn them in flour. Heat the oil in a pan and fry the herrings in portions, turning them golden brown. Put them in a bowl, let them cool down and pour the stock over them until they are covered. Cover them and leave them in the refrigerator for at least 24 hours. Wash the potatoes and cook in boiling water for about 20 minutes. Drain, rinse with cold water and remove the skin. Let the potatoes cool down and cut into slices. Peel and chop 1 onion. Heat clarified butter in a frying pan and fry the potatoes while turning. Add onion and fry. Season with salt and pepper.
Drain, rinse with cold water and remove the skin. Let the potatoes cool down and cut into slices. Peel and chop 1 onion. Heat clarified butter in a frying pan and fry the potatoes while turning. Add onion and fry. Season with salt and pepper. Arrange fried potatoes and herrings, serve garnished with dill. Serve with salad
waiting time approx. 24 hours