1. **Prepare the Lamb Shanks:**
Preheat your oven to 325°F (160°C). Season the lamb shanks generously with salt and black pepper.

2. **Brown the Lamb Shanks:**
In a large Dutch oven or heavy oven-safe pot, heat the olive oil over medium-high heat. Add the lamb shanks and brown them on all sides, about 4-5 minutes per side. Remove the lamb shanks and set them aside.

3. **Sauté the Vegetables:**
In the same pot, add the chopped onion, garlic, carrots, and celery. Cook for about 5-7 minutes, until the vegetables are softened.

4. **Deglaze and Build the Sauce:**
Pour in the red wine and bring to a simmer, scraping up any browned bits from the bottom of the pot. Stir in the beef or lamb broth, diced tomatoes, tomato paste, rosemary, thyme, bay leaves, dried oregano, and ground cinnamon if using. Mix well.

5. **Braise the Lamb Shanks:**
Return the browned lamb shanks to the pot, making sure they are submerged in the liquid. Bring the mixture to a simmer, then cover the pot with a lid and transfer it to the preheated oven. Braise for 2 1/2 to 3 hours, or until the lamb shanks are tender and falling off the bone.

6. **Serve:**
Remove the pot from the oven and discard the rosemary, thyme, and bay leaves. Transfer the lamb shanks to a serving platter and spoon the braised vegetables and sauce over the top. Garnish with chopped fresh parsley.

Enjoy these tender braised lamb shanks with