In a saucepan, finely chop half the onion and sauté it with a drizzle of olive oil. Remove the marrow from two ossobuco slices to use in the risotto. Once the onion is golden, add the four ossobuco slices, which you have previously dredged in flour and snipped at the edges with scissors to prevent curling. Brown the meat, season with salt and pepper to taste, then cook in the broth, adding a tablespoon of tomato paste for color.

In a large pan, start the risotto by sautéing the remaining half onion with a drizzle of olive oil, then add the rice and toast it. Begin adding the broth gradually. Halfway through cooking, add the marrow and the packet of saffron. When the rice is done, stir in the butter and Parmesan cheese until creamy.