Rinse the soaked chickpeas and kidney beans, then place them in a large pot with lentils. Cover with water or vegetable stock and bring to a boil. Reduce the heat and simmer for about 45 minutes until tender. Skim off any foam that rises to the surface.
In a separate pan, heat oil and add the sliced onions. Cook over medium heat until golden and caramelised. Stir in the minced garlic and turmeric. Allow the spices to bloom for a minute until fragrant, then add this mixture to the pot of legumes. This step adds depth and warmth to the base.
Stir in the spinach, parsley, coriander, dill, and spring onions. Simmer gently for about 15 minutes until the herbs have softened and the soup turns vibrant green. Keep the heat low to preserve the fresh aroma.
Break the reshteh noodles into shorter pieces and add them to the pot. Stir well to prevent sticking. Cook for around 10 minutes until the noodles are tender. If the soup becomes too thick, add a little hot water to adjust the consistency.
Stir in the kashk (or yoghurt if substituting) and season with salt and black pepper. Cook for another 5 minutes on low heat. The kashk lends the soup its distinctive tang and creamy texture. Do not boil after adding, as this may cause curdling.
While the soup simmers, fry the extra onion until crisp and golden. In a separate small pan, gently warm the dried mint in a spoonful of oil to create fragrant mint oil. Set aside both toppings.
Taste the soup and adjust seasoning as needed. Let it rest for about 10 minutes before serving. This allows the flavours to meld beautifully.
Ladle the soup into warm bowls. Top with a drizzle of kashk, fried onions, and mint oil in a circular pattern for an authentic Persian touch.
If you wish, sprinkle a few extra herbs or a pinch of sumac for gentle acidity. Serve with flatbread or pickled vegetables on the side.
Ash Reshteh is best served warm, allowing the creamy broth and herbaceous aroma to shine through. This dish celebrates community and comfort, making it ideal for sharing.