This recipe is part of the Epicurious Online Cooking School, in partnership with the Culinary Institute of America. To watch it being made, and to learn how to make other Italian classics, check out the videos.
1. In a small saucepan, warm the chicken stock. Keep warm.
2. In a large saucepan over moderately low heat, warm the olive oil. Add the onion and sauté, stirring occasionally, just until tender but before any color appears, about 5 minutes. Add the rice and saffron, and toast lightly for 1 minute without letting the rice or onion take on any color. Add the wine and cook until almost completely absorbed.
3. Add most of the chicken stock (it should come about 1/2 inch above the rice) and bring to a simmer. Cook the risotto, stirring occasionally, until the liquid has been absorbed and the rice is al dente, about 14 minutes. As the rice begins to absorb the liquid, add more as needed.
4. Once rice has absorbed almost all the broth, remove from the heat, add the butter and Parmigiano-Reggiano, and stir vigorously for about 1 minute to develop the surface starches. Season to taste with salt and pepper.
5. Serve the risotto immediately garnished with a piece of the meat marrow, if desired.
