Leave the partridge to sit in the fridge for 2-3 days, uncovered or lightly covered. This help to tenderise the meat.
Split the partridge in half and sprinkle on both sides with salt and pepper. Heat the oil in a deep casserole and brown the birds well. Add the garlic and onion and continue cooking until the onion is wilted.
Stir in the flour, then add the vinegar, wine, broth, salt, pepper, bay leaves and cloves. Cover and simmer, skin side down, for 45 minutes or until tender. Remove the birds to a warm platter.
Add the chocolate to the sauce and stir until dissolved. Return the birds to the casserole and cook, covered, for 10 minutes more.