Here, meltingly rich veal shanks combine wonderfully with the chewiness of orecchiette, ear-shaped pasta shells made of semolina (coarsely ground durum wheat).
Pat veal shanks dry and season with salt and pepper. In a deep large heavy skillet heat oil over moderately high heat until hot but not smoking and brown shanks on all sides. Transfer shanks to a plate and in skillet sauté onions, stirring, until golden, about 10 minutes.
In a blender or food processor coarsely purée tomatoes with juice and stir into onions with remaining sauce ingredients. Bring mixture to a simmer. Add shanks and cook, covered, over low heat 1 1/2 to 2 hours, or until meat is tender. Discard cloves.
Transfer shanks to a cutting board and cool slightly. Simmer sauce, uncovered, stirring occasionally, 15 minutes.
Using 2 forks shred meat. With a sharp knife remove marrow from shanks and chop. Stir meat and marrow into sauce and season with salt and pepper. Simmer sauce 15 minutes. Sauce may be made ahead, cooled completely, uncovered, and chilled, covered. 2 days or frozen 1 month.
In an 8-quart kettle bring 7 quarts of salted water to a boil. Cook orecchiette until al dente (about 6 minutes for fresh, longer for dried) and drain in a colander. In a large heated bowl immediately toss pasta with sauce.
