In a deep frying pan over medium heat, warm the olive oil. Add the onion and saute until soft, about 10 minutes. Add the garlic and half of the parsley and saute another 2 minutes. Pour the stock and 2 cups of water into a saucepan and bring to a simmmer. Add the rice to the saute pan and cook about 1 minute. Add ladelfuls of the stock and water mixture until all the liquid is absorbed. Stir constantly until the mixture is creamy about 25 minutes. Add the Parmesan Cheese, remaining parsley and artichoke hearts. Season with salt and pepper.