Heat 1 tbsp of olive oil in a large frying pan, then add the onion and sizzle until soft. Add the chorizo and fry for a few minutes until it starts to give off its oil, then tip in the rice and stir until all the grains are coated.Add the stock, saffron and paprika and stir. Turn down to a low simmer, cover and cook for 12-15 minutes, until the rice is almost tender. Stir in the prawns, peppers and another small ladleful of hot stock. Cook for another 3-4 minutes, or until the prawns are pink and cooked though. Stir in the parsley and serve.