Heat oil in a large deep-frying pan over a high heat. Add the onion, garlic & chorizo & cook for 2-3 minutes or until lightly golden. Add the paprika & saffron & cook stirring for a further minute. Add 4 cups of stock, stir & bring to the boil. Add the rice & stir to even the mixture.
Peel & devein prawns leaving tails intact. Push the prawns into the mixture, reduce the temperature to low & cook, without stirring for 15 minutes. Increase the temperature to medium & cook the paella for a further 4-5 minutes, adding the extra stock gradually if necessary, or until the rice is al dente. Season with salt & pepper & remove from the heat.
Cover surface with a clean towel & allow to rest for 10-15 minutes or until the liquid is absorbed & the prawns are cooked through. Place the parsley, lemon segments, olive oil & red wine vinegar into a bowl & toss to combine. Serve paella topped with parsley salad & aioli. Serves 4.