Whisk yogurt, salt, citric acid, flour, and egg in a large bowl.
Wash and chop the Swiss chard, and the purslane, and add to a deep bowl.
Pour enough boiling water over the Swiss chard and purslane to completely submerge. After five minutes, drain the water and rinse the Swiss chard and purslane with cold water. Squeeze to remove the excess water.
Chop the parsley, cilantro, green peppers, jalapeños, and onion.
Gradually add four cups of water into the yogurt. Whisk until thoroughly mixed.
Stir the Swiss chard, purslane, and the remaining herbs and vegetables into the yogurt.
Finally, add the rice into the soup.
Stir constantly, over a medium flame, until the mixture comes to a boil. If you don't, it will separate.
Stir occasionally during cooking, until all the vegetables and the rice are tender. If it becomes too thick, add more water to achieve the preferred consistency.
Booshala may be served hot or cold. I prefer hot! Not only when it comes to spiciness, but also in temperature!