Via: Jonathan Gregson
Preheat the oven to 180°C/gas mark 4. Place a large casserole dish over a high heat and add the olive oil. When smoking hot, add some of the oxtail pieces and fry on all sides for 4-5 minutes, browning well. Don't sear too many pieces at once or they will boil in their own liquid rather than fry. As the oxtail browns, transfer it to a colander over a plate and leave to drain off the excess fat.
Remove most of the fat from the dish and add the shallots, carrots and garlic. Return to a medium heat and cook, stirring occasionally, for about 10 minutes, until the vegetables are golden.
Add the wine and scrape the base of the casserole with a wooden spoon to mix in any flavoursome bits. Bring to the boil and simmer for 5 minutes until almost evaporated. Add the tomatoes. Tie together the thyme and rosemary sprigs with string and drop them in, then add the orange zest, bay leaves, cinnamon and star anise. Season and return the oxtail to the sauce, then bring to a simmer.
Cover the stew with a circle of baking parchment and a tight-fitting lid, and cook for 2½-3 hours. The meat is ready when it comes away from the bone easily.
Lift the oxtail from the sauce, place in a large bowl and leave to cool slightly. Discard the herbs, spices and orange zest from the sauce. When the oxtail is cool enough, pick the meat from the bones (discarding any excess fat that may have accumulated) and return it to the sauce, along with the pumpkin or squash and 300ml water. Bring to the boil, reduce the heat to a gentle simmer and cook, covered, for 30-40 minutes or until the pumpkin is soft. Season to taste.
To make the gremolata, mix together the parsley, lemon zest and garlic and set aside. Transfer the stew to a warm serving bowl and prinkle over the gremolata to serve.