1.In a pot, combine the washed red lentils, bulgur, green lentils, and rice.
2.Add 4 cups of hot water and bring to a boil over medium heat. Reduce the heat and simmer until the ingredients are softened.
3.In a separate bowl, mix yogurt, egg yolk, and flour. Add 2-3 ladles of the soup broth and whisk or blend until smooth.
4.Slowly pour the mixture into the boiling soup while stirring quickly. Continue stirring until the soup comes to a boil.
5.If the consistency is too thick, add hot water.
6.In a saucepan, melt butter and olive oil. Add finely chopped onion and sauté until translucent. Add the spices and simmer for 1-2 minutes, then remove from heat.