Clean the mussels thoroughly under running water. Remove beard threads. Discard opened mussels. Peel and finely dice an onion. Heat 20 g fat. Fry the diced onion and soup vegetables in it.
Add mussels and bay leaf. Deglaze with 1/8 litre wine and 1/4 litre water. Cook for about 5 minutes until the mussels have opened. Then take them out and keep them warm (do not use unopened mussels). Peel and chop the remaining onions and garlic. Clean and wash the celery, cut into thin slices and fry in the remaining fat. Deglaze with remaining wine and fish stock, bring to the boil. Season with salt and pepper. Coarsely chop the tomatoes, add them with the juice to the soup and simmer for about 10 minutes. Wash the fish, cut into bite-sized pieces, add and cook for about 5 minutes. Add the shrimps and mussels to the soup and let it simmer for a short time. Season to taste with salt, pepper and sugar.
Deglaze with remaining wine and fish stock, bring to the boil. Season with salt and pepper. Coarsely chop the tomatoes, add them with the juice to the soup and simmer for about 10 minutes. Wash the fish, cut into bite-sized pieces, add and cook for about 5 minutes. Add the shrimps and mussels to the soup and let it simmer for a short time. Season to taste with salt, pepper and sugar. Wash the dill, dab dry and pluck the flags. Serve the soup garnished with dill
Tip: You can also prepare fish stock yourself. Order approx. 1 kg of fish cuts from your fishmonger. Simmer them with 2 peeled onions, bay leaf, cloves, peppercorns and 1 litre of water for about 1 hour, then pour through a fine sieve.