6 pounds veal shanks, sliced crosswise into 2-inch pieces
1/2 cup all-purpose flour
2 teaspoons kosher salt
1/2 teaspoon freshly ground pepper
2 tablespoons olive oil
1/4 pound thickly cut pancetta, cut in 1/2-inch dice
3 leeks, cleaned and sliced, about 3 cups
1 bulb fennel, cut in 1/2 inch dice (fronds reserved)
2 cloves garlic, sliced
2 carrots, cut in 1/2 inch dice
1 tablespoon tomato paste
1 (14.5-ounce) can San Marzano or other good quality tomatoes, drained and crushed
1 sprig rosemary, about 4 inches long
2 sprigs thyme
2 bay leaves
3 strips orange zest, about 1 x 4 inches each
4 cups chicken, beef, or veal stock, divided
1 cup Cabernet Sauvignon or other red wine
Dredge the shanks in the flour, shake off excess, and season with the salt and pepper. Place a pan large enough to hold the shanks in one layer in the oven.
Heat pan for 5 minutes, add the oil, and then heat for 30 seconds more. Add the shanks and brown, turning once, for about 15 minutes. Remove from the pan and set aside.
Add the pancetta to the pan and cook until lightly browned, about 4 minutes. Add the leeks, fennel, garlic, carrots, and tomato paste and cook until tender, about 8 minutes. Stir in the tomatoes, rosemary, thyme, bay leaves, orange zest, 2 cups stock, and wine. Heat for about 3 minutes. Add the shanks plus any accumulated juices back to the pan, nestling into the vegetables and liquid.
Cover tightly and cook for about 1 1/2 hours, or until fork tender. Check the liquid level in the pan a few times during cooking to be sure it remains one-third of the way up the shanks. Add more stock if needed.
Remove from the oven, taste for seasoning, and sprinkle with 2 tablespoons chopped reserved fennel fronds.