For the cream of asparagus soup, peel and cut the asparagus into pieces and boil in salted water with a pinch of sugar for about 15 minutes.
Then drain the asparagus pieces, collecting the asparagus water. Heat 40 g butter in a saucepan and sweat the flour, slowly add the asparagus stock and mix well.
Add the soup powder and bring to the boil. Whisk egg yolk and cream and add while stirring. Do not boil! Add asparagus pieces and melt 80 g butter in the soup.
Season with salt and serve the cream of asparagus soup decorated with parsley.