Heat the oven to 180C (350F/Gas 4)
Heat 25g (scant loz/5 tsp) of the butter over a medium heat in a medium saucepan. Add the carrots and some seasoning and sweat until tender, then add the garlic and cook for a few minutes, stirring constantly. Use a slotted spoon to transfer the carrots to a bowl, then add the bacon to the pan. Fry until crisp, then lift into the bowl of carrots. Add the duck fat and celeriac (celery root) to the pan and cook the celeriac (celery root) slowly, on a low heat, adding a drop of water if necessary to prevent it catching and burning. Cook until lightly browned and tender, then use the slotted spoon to transfer it to the bowl of carrots. Add another 25g (scant loz 5tsp) of butter to the pan, and when hot, add the cabbage, season and cover with a tight-fitting lid. Cook the cabbage over a high heat, shaking the pan occasionally to prevent it catching. Cook until tender, then stir in the other cooked elements along with the cream. Check the seasoning and set aside.
Season the partridges inside and out. Heat an ovenproof frying pan (skillet) over a medium-high heat. Add 2 tablespoons of oil to the pan if necessary. Brown the other partridges in the same way. Transfer to the roasting pan with the first two, then place in the oven. Roast for 4 minutes on the first side, flip onto the other side for 4 minutes and then 2 minutes on their back – until pink. Remove from the oven and loosely cover with foil. Leave to rest in a warm place, breast-side down, for 10 minutes.
Add 1-2 tablespoons of the oil to the partridge frying pan (skillet), then add the carrot, onion and celery. Sweat over a medium heat, then add the wine. Reduce by half, then add the stock (broth). Reduce it by a third. Check the seasoning, then pass through a fine sieve. Return to a clean pan and whisk in the remaining 50g (5tbsp) of butter, then transfer to a warm jug to serve. While the birds are resting, reheat the cabbage. Carve the partridges and serve on the cabbage with the sauce.
