1. To make the marinade, place the olive oil, thyme, orange rind and garlic in a large zip-lock bag and add the ribs. Then rub this marinade mixture into the ribs. Chill for at least 4 hours over overnight is best. Allow to come back up to room temperature before cooking.
2. Preheat the oven to 150°C, gas mark 2. Heat a frying pan over a high heat.
3. Wipe the marinade off the ribs and season them, reserving the marinade. Add to the frying pan in batches and cook for 6-8 minutes on each side until golden brown.
4. Heat the oil in a large heavy-based casserole (big enough to hold the ribs in one layer). Add the onions, carrots and celery along with the reserved marinade and cook over a high heat for 5 minutes.
5. Pour in the wine and bring to the boil, then cook for a few minutes scraping the bottom of the casserole with a wooden spoon to remove any sediment.
6. Pour in the stock and then return the ribs to the pan and push down to make sure they’re all submerged.
7. Cover with a lid and transfer to the oven and cook for 2-3 hours or until the ribs are completely tender but still holding their shape.
8. In the meantime, make the cheesy polenta. Bring the milk to the boil with 500ml of water, the bay leaf and thyme. Turn off the heat and leave to infuse for 20 minutes, then take out the herbs and bring back to the boil.
9. Add the polenta in a thin steady stream, whisking constantly. Cook for 1 minute (or according to packet instructions) until thickened, then remove from the heat and stir in the butter and Parmesan. Season to taste with salt and pepper and serve at once.
10. To make the gremolata, mix together the garlic, parsley and lemon rind in a small bowl and set aside until needed.
11. When the ribs are cooked, transfer them to a dish with a tongs and cover with cling film. Strain the braising liquid into a pan, discarding the vegetables and spoon off the excess fat. Whisk in the treacle then simmer over a low heat until reduced by half, skimming off any fat and scum that rises to the top. Pour back over the ribs.
12. Spoon the soft cheesy polenta into wide rimmed bowls and arrange the ribs on top, then spoon over some of the cooking juices and scatter over the gremolata to serve.