Wash, rinse, and soak barley in cold water for about 2 hours. Do the same with the rice.
In a large pot, on high heat, saute onions with four tablespoons of vegetable oil until it is golden brown. Drain the pearl barley and add to the fried onions; stir until the grains are well coated; then add 1 litre of water. Lower heat and leave to simmer for 40 minutes. Drain the rice and add to the pot and add a litre of vegetable stock; leave to simmer for 30 minutes on low heat.
Add the chopped herbs; stir thoroughly, add water according to the thickness, and leave to simmer on low heat for 15 minutes—season with salt and pepper according to taste.
In a small pan, heat two tablespoons of vegetable oil and add the dried mint and turmeric powder; stir the mixture into the soup. And finally, add a drizzle of lemon juice.
For serving, put into a small bowl, top with yoghurt and drizzle some of the fried mint.