Wash the herbs. Make sure to keep the parsley and mint separate.
Cut the meat into chunky pieces. If the meat you have is on the bone, don’t throw the bone away. It will give your stew amazing flavour.
Finely chop the onion.
Fry the meat in 3 tbsp of vegetable oil until golden brown from each side. Remove the meat from the pan and gently fry the chopped onions in the same oil for about 10 minutes.
Return the meat to the pan or transfer both, meat and onions, plus bones, if you have them, to the pan you want to cook your stew in. Boil 1 litre ( 1 1/4 cups) of water and add it to the meat. Add the tomato paste, turmeric, black pepper and salt, put on the lid and let the meat simmer over low to medium heat for 1 hour and 45 minutes.
Finely chop the parsley and mint (keeping them separate).
Fry the chopped parsley in 3 tbsp of veg oil for about 8 minutes. Remove it from the pan. Then fry the mint in 1 tbsp veg oil for only 30 seconds. Add the herbs to the stew and let it continue simmering.
10 minutes towards the end of the cooking time, peel the rhubarb and chop it into about 1″/ 3cm long pieces and add it to the stew. You can turn the heat off now, the rhubarb will cook in the hot stew in no time.
Serve your Khoresh-e Rivas with aromatic rice, red onions, salad, yoghurt and/or fresh herbs. Enjoy!