In a non-stick deep based frying pan heat the oil and sauté the onion and garlic until lightly brown.
Add the chorizo and cook for a further 5 minutes.
Add the risotto rice, making sure you stir the rice round the pan till all the oils are absorbed (approx 2-3 minutes). Then add the white wine, green beans, salt and pepper to taste, and cook until the fluid reduces down.
Add 250 ml of your stock. Cook until this has reduced right down (about 6-8 minutes), and then use another 250 ml of the stock, reduce, add 250 ml of stock and reduce. Add the last of the stock and the basil, and cook until the stock reduces down. Then sprinkle the Parmesan, add the butter and mix thoroughly. Take the risotto off the heat, place a lid on the pan until the butter is melted, then serve!