For the creamy mustard soup, peel and finely dice the onion and garlic. Heat butter in a saucepan and sauté onion and garlic without letting them take color.
Add flour and stir to a paste. Then deglaze this porridge with white wine and simmer to a thick sauce. Gradually add the broth until it is used up.
Add whipped cream and use a blender to puree the soup. Remove the pot from the heat, add the mustard and puree again.
Fold in the chopped chives and garnish the creamy mustard soup with parsley.