Chop the broken asparagus. Rub the lemon peel with the grater and set aside. Peel the asparagus spears and cut into short pieces. Set aside and cover.
Melt 2 tablespoons of butter in the pan and sweat the broken asparagus pieces. Deglaze with the broth and season with lemon juice, sugar, salt and pepper. Add 200 ml of white wine
Let the soup simmer for 30 minutes and then strain it through a sieve.
Add half of the asparagus pieces and the rest of the white wine to the soup and simmer for another 20 minutes. Puree finely with the magic wand and add the sweet cream. Knead the 2 tablespoons of cold butter and the 2 tablespoons of flour. Thicken the soup with the flour butter.
Melt 1 tablespoon butter in a pan and fry the remaining pieces of asparagus and the asparagus tips. Season with salt and pepper.
Melt 1 tablespoon of olive oil and 1 tablespoon of butter in a second pan. Fry the prawns, the spring onions cut into small rolls, the finely chopped garlic and the sprigs of rosemary.
Add the fried asparagus pieces to the hot soup. Place the prawns on top of the asparagus soup and decorate with the grated lemon zest.