Pick over the rice carefully to remove its many small solid particles of grit. Wash the rice by placing it in a large container and covering it with lukewarm water. Agitate gently with your hand, then pour off the water. Repeat five times until the rice is completely clean. Heat 4 tablespoons oil in a wok over medium heat. Add the onion slices and fry for 15 minutes until golden brown. Add the rice, cardamom, and saffron rose water, and stir-fry for 1 minute. Add the salt and warm stock, and bring to a boil; stir gently once. Reduce heat to medium-low, cover tightly and cook for 30 minutes.

Remove from heat, add the oil, and pistachio, and sprinkle the dill and rose petals over the top, and fluff with a fork. Cover and let stand for 10 minutes before serving.