First, make the vegetable broth.

Wash and trim the carrot, cut it in half, and set aside in a bowl.

Peel the onion, cut it in half, and add it to the bowl with the carrot.

Wash and trim the celery stalk, cut it into several pieces, and add it to the bowl with the other vegetables.

Place the vegetables in a pot, fill with water, and cook for about 30 minutes.

Meanwhile, wash and trim another celery stalk, finely chop it, and set aside in a bowl.

Wash and trim another carrot, finely chop it, and add it to the bowl with the celery.

Peel another onion, finely chop it, and add it to the bowl with the other vegetables.

In a pot, heat some olive oil and add the chopped vegetables you just prepared. Sauté until softened, then add the beef shank. Season with salt, black pepper, and chopped parsley, and brown for about 10 minutes.

Once well browned, add a few ladles of vegetable broth and cook for about 30 minutes.

After this time, turn off the heat, remove the marrow from the beef shank, and set it aside in a small bowl.

In a pan, heat some olive oil and add the finely chopped onion. Sauté until softened, then add the rice and toast for a few minutes.

Gradually add the vegetable broth and cook the rice until done.

In a small bowl, add a little vegetable broth and the saffron. Stir well with a spoon and set aside for a moment.

Ten minutes before the risotto is done, add the saffron and continue cooking.

One minute before the risotto is ready, turn off the heat, move the pan off the burner, and stir in the butter, marrow, and grated Parmesan cheese.

Once everything is well combined, let it rest for a few minutes.

Plate and serve.