Peel the onion, wash it, cut it into thin slices and brown it in a pan with the oil over low heat. Add the broth, raise the heat and ring to a boil.
Pour the Originario rice and cook it for 11 minutes, stirring occasionally. Meanwhile, wash and chop the parsley. Once the soup is ready, add the parsley together with the grated Parmigiano Reggiano cheese.