Begin by heating the butter and oil in a flameproof casserole and frying the rabbit joints quickly to brown them all over. Now remove them to one side and fry the onions, garlic and bacon for about 10 minutes. Then sprinkle in the flour, stir and cook for a minute or two before gradually stirring in the cider and the stock. At this stage add the rabbit joints, together with the thyme and crushed juniper berries. Bring everything to simmering point, then add the sliced mushrooms and a seasoning of salt and freshly milled black pepper. Cover and simmer the rabbit very gently for about an hour, or until it's tender.