Preheat your oven to 350°F (175°C).

Season the beef shank slices with salt and pepper on both sides.

In a large, oven-safe pot or Dutch oven, heat the olive oil over medium-high heat. Add the beef shank slices and sear them for about 4-5 minutes on each side until browned. Remove the beef and set aside.

In the same pot, add the diced onion, carrots, and celery. Sauté for about 5 minutes until the vegetables are softened. Add the minced garlic and cook for an additional minute.

Pour in the white wine, scraping the bottom of the pot to deglaze. Let it simmer for about 2-3 minutes.

Stir in the diced tomatoes, beef broth, thyme, and bay leaf. Return the beef shank slices to the pot, ensuring they are submerged in the liquid.

Bring the mixture to a gentle simmer, then cover the pot and transfer it to the preheated oven. Cook for 2.5 to 3 hours, or until the meat is tender and falling off the bone.

Once done, remove the pot from the oven. Discard the bay leaf and stir in the lemon zest and chopped parsley before serving.