Red Wine-Braised Lamb Shanks

Position rack in lowest third of oven; preheat to 350°F. Place a roasting pan next to the stove.

Pat lamb shanks dry. Season with 1/2 teaspoon each salt and pepper. Heat oil in a large pot over medium-high heat. Add 3 shanks and cook, turning, until browned on all sides, about 7 minutes. Transfer to the roasting pan. Repeat in 2 more batches with the remaining shanks.

Reduce heat to medium and add onions, carrots and celery to the pot. Cook, stirring occasionally, until soft, about 5 minutes. Add garlic and cook for 1 minute. Add flour and tomato paste and cook until browned, 3 to 5 minutes.

Increase heat to medium-high and add wine. Cook, scraping up any browned bits, until the liquid is reduced by half, 3 to 5 minutes. Stir in broth, tomato puree, bay leaves, rosemary and the remaining 1/2 teaspoon each salt and pepper. Bring to a simmer.

Pour the tomato mixture over the shanks in the roasting pan. Cover with foil and transfer to the oven. Bake until the meat is very tender and falling off the bone, 2 1/2 to 3 hours. Transfer the shanks to a serving dish and cover to keep warm.

Carefully place the roasting pan over two burners on the stovetop. Skim off any fat and discard the bay leaves and rosemary. Simmer the sauce over medium heat until thickened, about 4 minutes. Stir in vinegar. Serve the shanks with the sauce and garnish with parsley, if desired.