6 leeks, white and light green parts only, trimmed, halved lengthwise, cut crosswise into thing half-moons, rinsed thoroughly and drained
1 cup basic tomato sauce (for quick results, try my Mario Batali pasta sauces)
3 cups brown chicken stock
2 cups red grapes, wine grapes such as Sangiovese, or, even better, Concord grapes, halved and seeded
Preheat the oven to 375F.
Rinse and dry the lamb shanks, and season them liberally with salt and pepper. In a very large heavy-bottomed Dutch oven, heat the olive oil over medium-high heat until smoking. Add the lamb shanks, 5 at a time, and seat until dark golden brown all over, 10 to 12 minutes per batch. Remove the shanks and set them aside.
Add the onions, garlic, carrots and leeks to the pot, and cook until softened, 8 to 10 minutes.
Add the wine, tomato sauce and stock to the vegetables and bring to a boil. Return the lamb shanks to the pot and bring back to a boil. Cover the pot tightly, place it in the oven, and bake for about 1 1/2 hours, until the meat is fork-tender.
Remove the pot from the oven, check the sauce for seasoning, and then add the grapes. Stir them in gently, and serve directly from the pot.
(Mario Batali is the owner of Babbo, Lupa, Otto and other renowned restaurants. His latest book is "Molto Batali," published by Ecco. Follow Mario on Twitter @mariobatali.)