Step 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, or overnight if possible. Allow to come back up to room temperature before cooking.
Step 2
Preheat the oven to 150°C/300°F/Gas Mark 2. Heat a frying pan over a high heat. 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.
Step 3
Heat the oil in a large heavy-based casserole dish (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. Pour in the wine and bring to the boil, then cook for a few minutes scraping the bottom of the casserole dish with a wooden spoon to remove any sediment. Pour in the stock, add the ribs in one single layer and cover with a lid. Transfer to the oven and cook for 2-3 hours or until the ribs are completely tender but still holding their shape.
Step 4
When the ribs are cooked transfer them to a dish with a tongs and cover with clingfilm. Strain the braising liquid into a pan, discarding the vegetables and 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.
Step 5
To make the gremolata, mix together the garlic, parsley and lemon rind in a small bowl and set aside until needed.
Step 6
Spoon the 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.