Heat butter in a pot, dust with flour and sauté. Gradually deglaze with broth while stirring, bring to the boil, simmer for 3-4 minutes at low heat
Meanwhile grate the cheese finely. Wash lovage or parsley, shake dry and chop finely. Stir cheese and cream into the soup, bring to the boil again and then season to taste with salt and pepper. Arrange in soup bowls sprinkled with lovage or parsley