Preparation. Peel and finely chop the onion. Heat the fat in a pot and sauté the onion. Dust with flour and sauté for about 1 minute. Pour in 1 litre of water and white wine, bring to the boil and add the paste while stirring.
Let simmer for about 10 minutes. Stir in 250 g crème fraîche, season to taste with salt, pepper and lemon juice. Wash the dill, dab dry and pluck flags from the stalks. Pour the soup into small bowls and serve each with crabs, the rest of the crème fraîche and dill.
With 10 people: