Wash the asparagus thoroughly, cut off the woody lower ends. Peel the asparagus. Put the asparagus peel in 1.25 litres of boiling salted water (with a pinch of sugar). Cover and simmer for about 20 minutes.
In the meantime cut the asparagus into pieces. Drain the asparagus skin, let it drain well and collect the asparagus water. Put the asparagus water back into the pot, bring to the boil and add the asparagus pieces. Cook for about 15 minutes.
Press the sausage meat as small dumplings from the skin. Heat the oil in a pan and fry the dumplings all around. Drain the asparagus, collect the asparagus water and measure 1 litre. Heat butter in a pan, dust with flour, sweat it and gradually add asparagus water and cream, stirring constantly.
Bring to the boil, season with salt, pepper, sugar and wine. Add asparagus and meatballs, heat up again briefly. Serve soup in small bowls. Serve garnished with chervil if desired.