1. Preheat the oven to 180°C. Stuff a thyme sprig into each partridge, then wrap 4 slices of pancetta around it and tie in place.
2. Heat 1 tablespoon of the butter in a large, heavy-based, ovenproof pan and sear the partridges until lightly golden all over.
3. Turn the partridge’s breast down and transfer the pan to the oven to roast for 6 minutes.
4. Turn the birds over and add the port to the pan, then roast for a further 5–6 minutes until the partridges are done.
5. When the birds are ready, remove from the oven and set aside to rest for 5 minutes.
6. Reduce the roasting juices in a pan with 2 tablespoons of stock for spooning over the finished dish.
7. While the partridges are roasting, blanch the Savoy cabbage in a saucepan of boiling salted water for about 7 minutes until tender; drain well.
8. Heat the remaining butter in the empty pan and briefly fry the garlic. Add the chopped vegetables and chestnuts and cook for 4–5 minutes until softened. Add the cabbage and stock. Bring to a simmer, then cook over a low heat, stirring frequently, for 10–15 minutes until the stock has reduced and the cabbage becomes slightly caramelised.
9. Season with salt and pepper. Spoon the cabbage on to warmed plates, set the partridges on top and drizzle over the roasting juices.