01 - Set the oven to 320°F to prepare for braising.
02 - Lightly season the lamb shanks with salt and black pepper.
03 - Heat olive oil in a Dutch oven over medium-high heat. Sear lamb shanks on all sides until deeply browned, approximately 8 minutes total. Remove and set aside.
04 - In the same pot, add onion, carrots, and celery. Cook for 5 minutes until softened, then stir in minced garlic and cook for an additional minute.
05 - Pour in the red wine, scraping the bottom of the pot to release browned bits. Let simmer for 2 minutes to reduce slightly.
06 - Stir in diced tomatoes, beef stock, rosemary, thyme, and bay leaves. Return the lamb shanks to the pot, ensuring they are partially covered by the liquid.
07 - Bring the mixture to a simmer, cover the pot, and transfer to the preheated oven. Cook for 2½ hours, turning the lamb once halfway through, until the meat is tender and falls off the bone.
08 - Discard bay leaves and herb stems. Skim excess fat if desired. Serve lamb shanks with the rich sauce and vegetables.