Place the stock in a large saucepan and bring to the boil over a high heat. Reduce the heat and keep at simmering point.
In a large, heavy based saucepan on medium heat add 1/2 tbsp olive oil, 1 tsp sea salt and stir fry the onion until it is translucent
Add the rice and stir fry for 1-2 minutes.
Gradually add the simmering stock, 1 cupful at a time, stirring constantly and making sure the stock is absorbed before you add more.
This should take about 20 minutes, by which time the rice should be al dente and creamy.
Remove the saucepan from the heat, and stir in the lemon zest, lemon juice and pepper. Cover the saucepan and leave to sit for a few minutes while you do the prawns.
Pound up the chilli and garlic in a mortar and pestle (you can chop these if you don't have a mortar and pestle, but the flavour absorbs into the prawns much better this way)
Place the remaining 1/2 tbsp olive oil in a frying pan, and bring up to a high heat. Season the prawns with salt and pepper, and then add to the hot pan, Cooking for 2 minutes. Add the chilli and garlic, and cook for a further 1 minute. Remove from the heat and set aside.
Stir the risotto and divide between 4 bowls. Toss the prawns with the parsley, and then place on top of the risotto. Serve with lemon wedges.
This is lovely served with asparagus or fresh mange tout.