01 - Set the oven to 320°F to prepare for braising.
02 - Generously season lamb shanks with salt and black pepper.
03 - Heat olive oil in a large Dutch oven over medium-high heat. Brown the lamb shanks on all sides for approximately 8 minutes, then remove and set aside.
04 - Add chopped onion, sliced carrots, and chopped celery to the pot. Cook for about 5 minutes until softened. Stir in minced garlic and sauté for an additional minute.
05 - Pour in the red wine, scraping the bottom of the pot to release browned bits. Allow the mixture to simmer for 2 minutes.
06 - Add diced tomatoes, beef stock, rosemary, thyme, and bay leaves to the pot. Return lamb shanks, ensuring they are partially submerged in the liquid.
07 - Bring to a simmer, cover the pot, and transfer to the oven. Braise for 2.5 hours, turning the shanks halfway through, until meat is tender and easily falls from the bone.
08 - Discard bay leaves and herb stems. Skim excess fat from the sauce if desired. Serve lamb shanks accompanied by sauce and vegetables.