Peel off the asparagus and cut into pieces approx. 4 cm in size. Cook the asparagus pieces together with the sugar, butter and a splash of lemon juice in the vegetable stock for about 20 minutes. Then puree the asparagus in the broth with a hand blender. Add the sweet and sour cream and the honey mustard and bring to the boil again. Season to taste with salt and pepper. Serve hot.
Tip: To get a finer consistency, the soup should finally be poured or strained through a sieve so that the fibrous asparagus remains are filtered out.