Heat 5 tablespoons oil in a non-stick frying pan over medium heat. Add the dried mint, parsley and cilantro; fry for 4-5 minutes. Set aside.
Heat 3-4 tablespoons oil in a pot over medium heat. Add the onions and saute until lightly golden. Increase heat to medium-high; add the beef and saute until brown on all sides.
Add the turmeric powder and mix well. Add 4 1/2 cups hot water. Cover the pot and bring to a boil. Reduce heat to medium and simmer covered until beef is tender, about 60-70 minutes (cooking time depends on the thickness of the meat).
Then add the fried herbs, crushed tomatoes, pepper and salt. Simmer covered until beef is completely cooked (about 45-55 minutes), stirring occasionally. Add more hot water during cooking, if necessary.
Add the rhubarb and sugar to the pot, lower the heat to a gentle simmer and cook for an additional 12-15 minutes or until the rhubarb is done. Avoid over-cooking the rhubarb, it would fall apart fast. Serve with Persian Rice.