Heat the oil in a large frying pan and gently cook the onions and garlic until they are golden brown and slightly caramelised.
Transfer the onions and garlic to a large bowl and mix in the rice, saffron and chopped coriander. Season with salt and pepper and shape into patties.
Wipe the pan clean with kitchen paper and heat a little more oil. Fry the patties for 2 minutes on each side and served sprinkled with the parmesan.