Clean and wash the offal and meat. Put them in a pressure cooker, pour in the desired amount of water and close it. Put it on the stove on the highest setting, once boiling lower to the lowest.
After 30 min., remove from the stove and wait for it to cool. Take the offal and meat out, strain the broth into another pot.
Stir the yolks, yoghurt and flour. Scoop a ladle of the hot soup and pour it into this mixture, while stirring nonstop. After you add 4 ladles' worth, mix and add it back to the main soup, again using the ladle.
Return to the stove, salt to taste, add black pepper, the remaining spearmint and once the soup comes to a boil again, remove from the heat.