Season the duck. In a flameproof casserole, heat the fat until sizzling, put in the duck legs and fry until golden all over. Add the onions, lower the heat and cook gently for 10 minutes.
Pour off the fat, pour the wine into the casserole and bring to the boil. Add the bouquet garni, peppercorns, garlic, diced bacon and some salt and cook for about 30 minutes, adding the prunes 5 minute