Wash the potatoes thoroughly and cut in half or quarters depending on size. Peel and finely chop the onion. Peel carrots and cut them into approx. 0.5 cm thick slices.
Bring 500 ml water and 1 teaspoon salt to the boil. Add potatoes, onion and carrots and cook covered for about 5 minutes. Meanwhile clean and wash the cauliflower and cut it into small florets. Add the cauliflower to the pot, bring to the boil again and continue cooking for about 5 minutes.
In the meantime, sort out the spinach, wash and drain well. Stir 100 ml milk and flour until smooth. Pour 500 ml milk and mixed milk into the vegetables, bring to the boil again. Add peas and continue cooking for about 10 minutes.
Drain the prawns in a sieve.
Meanwhile, wash the dill, shake dry and cut finely. Wash parsley, shake dry and chop finely. Clean and wash radishes and slice them into thin slices. Season soup well with salt, pepper and lemon juice.
Stir in about 3/4 of the dill and spinach. Arrange soup in deep plates. Sprinkle with radishes, prawns and dill. Serve with rye bread with butter and dill.