1- Wash the lentils. Put them in meat stock and 1 cup of water. Cook for 35-40 minutes until they are tender. Pass them through a sieve. 2- Melt the butter in anothe saucepan. Add chopped onions and fry them lightly for 7-8 minutes. Add flour. Brown for 1 minute more. Add them to the meat stock with the lentil puree. Add slat and pepper and let simmer. 3- Beat the egg yolks with cold milk. Add to the boiling soup, mix well. Turn the heat off as soon as it starts boiling. Serve with bread cubes fried in oil.