How to make
Saute the chopped onions in half the butter and 2 tbsp water.
Add the flour, tomatoes and 2 cups water. Once it comes to a boil, add the mince.
Boil the soup another 15 or so minutes on moderate heat.
Add the finely chopped parsley, celery and remaining butter. Remove from the heat and thicken with the egg yolks and milk.