Roll the meatballs in flour and put them in a pot with boiling salted water. Boil until ready.
In a deep bowl, mix the rest of the eggs, yoghurt and flour. Scoop from the broth in which you boiled the meatballs and mix it in slowly, in order not to curdle the eggs.
Return the sauce to the pot while stirring nonstop and leave to boil another 10 min. in order to obtain a thick sauce.
Garnish with finely chopped parsley.