In a pot, combine beef broth and water, season it with salt and ground black pepper. Bring to boil.
Now drop the meatballs into the pot one at a time. Let it boil.
In the meantime, heat olive oil in a pan, saute onion for 3 minutes, add the tomatoes and garlic. Mix well then add the cooked rice into the pan and mix for another 3 minutes.
After 3 minutes, add the rice mixture into the meatballs mixture, then add potatoes, carrot, and celery. Boil for 20 minutes.
After 20 minutes, add tomato sauce, coriander seed, and cilantro. Cook for 10 minutes.
Ladle soup with about 5 meatballs in a bowl.