Preheat the oven
Heat the oven to 325° F and set out a Dutch oven or other heavy ovenproof pot.
Prep the aromatics
Finely dice the Onion and Carrots, and cut the Thick-Cut Bacon into small pieces. Strip the Rosemary Leaves and Sage Leaves from their stems, mince the Garlic, and mix them with the Kosher Salt and Lemon Zest to make Rosemary Salt.
Season and dredge
Pat the Shanks dry, season them all over with black pepper and a light sprinkle of rosemary salt, then coat each piece in Flour and shake off the excess. Set the floured shanks on a tray while you heat the pot.
Brown the meat
Heat the Dutch oven over medium-high with the Olive Oil and Butter. Sear the shanks in batches for 4 to 5 minutes per side until a deep brown crust forms, adding a little more oil if the pot looks dry, then move them to a plate.
Build the sauce
Lower the heat to medium. Add the Thick-Cut Bacon and cook until it renders fat and starts to brown, then stir in the Onion and Carrots and cook until they soften. Stir in the Tomato Paste and cook it for a minute until it darkens, then add the Thyme, Rosemary, and Bay Leaf. Pour in the Dry Wine — white for veal or pork, red for beef or lamb — and scrape up the browned bits, then add the Canned Peeled Tomatoes and Beef Bone Broth, breaking the tomatoes up with a spoon as they go in. Bring the sauce to a gentle simmer and nestle the shanks back in, bone-side up.
Mix gremolata
Finely chop the Parsley and mix it with the lemon zest and garlic in a small bowl. Set the gremolata aside until serving.
Braise in oven
Cover the pot tightly and bake for 2 1/2 to 3 hours until the shanks are fork-tender and the meat is almost falling from the bone.
Reduce the sauce
Lift the shanks to a platter and keep them warm. Remove the herb stems and bay leaf, then simmer the sauce uncovered over medium heat for 10 to 15 minutes until it thickens enough to coat a spoon. Taste and adjust with a little more rosemary salt if needed.
Serve and garnish
Spoon the sauce over the shanks, scatter the gremolata on top, and serve right away while everything is hot.
