Heat the oil in a large, ovenproof frying pan over a medium heat. Fry the partridges on all sides for 3-4 minutes, until browned all over.
Transfer the pan to the oven and roast for 12-15 minutes. Baste with the fat a couple of times during cooking. They are cooked when the juices run clear when the partridges are pierced in the thickest part of each thigh using a skewer.
For the blackberry sauce, heat 2 tablespoons of the butter in a saucepan over a medium heat. When the butter is foaming, add the shallot, garlic and thyme and fry for 2 minutes until softened.
Add the remaining blackberry sauce ingredients, apart from the blackberries, and cook, stirring well, for 5-8 minutes until the sauce has thickened.
Just before serving, strain the blackberry sauce through a fine sieve into a clean saucepan. Stir in the remaining butter and the blackberries. Pour over the partridge once ready.
We suggest serving this dish with fondant potatoes, a red cabbage puree and wilted kale.