Take a large double bottom saucepan to hold the heat of the rice, boil the water with sea salt and 3 stock cubes, pour in the rice and cook on high heat for 5 minutes, then cook the rice for a futher 10 minutes on a low heat covered by a lid. After 10 minutes remove from heat and mix the rice with a wooden spoon, cover with a dishcloth and the lid on top. In the meantime put the sausage meat in a pan and cook on a low heat for about 5 minutes making sure it does not stick, then add the onion and continue to cook for another 10 minutes, finally add the butter. The rice at this point will be cooked, so take the sausage meat and pour it onto the rice mixing well and adding the grated Parmesan cheese and a sprinkling of nutmeg. Serve on a hot plate.