4 to 5 pounds oxtail, cut into 3-inch pieces at the butcher
Salt and freshly ground black pepper
Flour, for dredging
1/4 cup olive oil
1 medium yellow onion, chopped
1 large carrot, chopped
3 whole celery ribs, chopped
1 (28-ounce) can plum tomatoes, crushed
3 cups dry red wine
2 rosemary sprigs
2 thyme sprigs
2 bay leaves
4 cloves garlic, peeled and smashed
1/4 teaspoon freshly grated nutmeg
Preheat the oven to 300°F.
Pat the meat dry with paper towels then dust with the flour, tapping off any excess. Season with salt and pepper on all sides.
Place a 6-quart Dutch oven or other heavy-bottomed, oven-safe pot with a tight-fitting lid over medium-high heat. Add the oil, and when glistening, add the meat (metal tongs come in handy here) and sear on all sides, about 8 to 10 minutes. Work in batches if necessary to avoid overcrowding.
Transfer the meat to a plate. Add onion, carrot and celery and cook, stirring frequently, until browned, about 5 to 7 minutes. Add the tomatoes with their juices, wine, rosemary, thyme, bay leaves, garlic and nutmeg. Bring to a boil for 5 minutes.
Add the meat and enough water to just barely cover meat. Return to a boil, then cover the pot and transfer it to the oven. Cook for 3 to 4 hours, until the meat is fork tender and falling off the bones.
Remove the pot from the oven and transfer the pieces of meat to a plate. Skim any visible fat from the surface of the sauce. Pick the meat from the bones, pulling away and discarding any pieces of fat, and then return the meat to the pan. Pluck out the bay leaves, and sprigs of rosemary and thyme. Season the sauce with salt and pepper.
Serve atop gnocchi or any pasta meant to withstand a hearty sauce. The ragù can be made a few days ahead; keep covered and refrigerated, then reheat over medium-low heat.