How to cook
Put the shank to boil in a pressure cooker with some black pepper and enough water. Then strain the broth and tear the meat finely.
Finely chop the celery, carrots, peppers and onions and saute them in a little preheated oil.
Add the meat, chopped potatoes, black pepper and broth. Leave the soup to boil for 30 minutes on low heat.
A few minutes after removing the ready soup, thicken it with the beaten together yogurt, flour and egg yolks + 1 tsp vinegar. Serve the soup with a little chopped parsley.