Chop the onions and mushrooms and fry them in the butter. Deglaze with the vegetable stock. Whisk the cream with the flour and stir into the soup. Bring to the boil briefly.
Peel the tomatoes and cut them into small cubes, also dice the eggs. Turn off the stove, add the eggs and tomatoes, let them get hot. Season with salt, pepper and nutmeg and serve sprinkled with parsley.