How to Make An Onion Soup Call'd the King's Soup
- Place onions, milk, mace, butter, and salt in a saucepan. Bring to a boil, then reduce heat and cook slowly for 30-40 mins., or until onions are very tender. Pick out mace blades & discard.
- Beat egg yolk in a small bowl, then add a little of the hot soup, beating constantly. Pour egg mixture into soup and cook a minute or two to thicken slightly.
- Sprinkle each serving with finely chopped parsley, then add a few croutons.