1 whole duck (sliced duck breast may also be used as a substitute)2 pounds potatoes, peeled2 cups pre-roasted chestnuts, shell removed1/2 cup olive oil2 onions, chopped4 garlic cloves2 cups mushrooms, sliced1 cup white wineJuice of one orange1 dozen dry prunes2 carrots, sliced2 tablespoons Worcestershire sauceRosemary to garnishSalt to taste