Tarhana is a traditional, spicy Turkish soup common throughout Anatolia. Tarhana powder is prepared by mixing plain yogurt, flour, and grated vegetables like red pepper, tomato, and onion into a thick paste that is left to ferment for several days. The paste is then divided up, dried, and crumbled to make tarhana powder. Put one full spoon of tarhana and 1.5 glass of water in a pot for each person. Stir continuously 15 mins with medium heat. Add some butter and serve.