Turn off heat. In a frypan, saute the onions in oil until transparent. Add mint or cilantro and stir-fry until onions are browned. Add this mixture to the soup with additional water and salt to taste. Bring to a boil again and cook 15 minutes.
Orzo is the small pasta that looks like rice.
Cook until rice is tender, 20-25 minutes. Make a paste of the yogurt, salt, and flour, and stir into the rice. Add enough water to nearly fill the pan. Bring to a boil again and cook 10-15 minutes. Just before it is finished cooking, add parsley or mint.