Marinate chicken pieces overnight. Cook peeled pearl onions in 2 T butter and sugar plus 4 T water. Simmer until almost dry then shake the pan often to caramelize evenly. Soak prunes in Madeira overnight. Cook bacon until golden brown. Drain in paper towels. Discard fat. Cook chopped onions in 2 T butter until soft.Add garlic, cook 1 minute and turn off heat. Brown chicken pieces in 2 T oil in skillet where bacon was cooked, place legs and thighs first, transferring pieces to pan with onions as they brown. Season with salt and herbs. Turn heat on and add 1 cup broth ,wine from marinade, red wine and Madeira where prunes have soaked. Simmer legs and thighs 15 minutes while you brown the rest of the chicken. Transfer browned pieces to the pot with the legs and thighs.Simmer all for 45 minutes longer. Transfer chicken pieces to an ovenproof dish and keep it in warm oven 200 degree while you finish the sauce. strain sauce. Make a roux with the butter and flour. Stir in sauce, 1 T Port or Madeira.Add prunes and pearl onions, boil 1 minute. Pour over chicken. Sprinkle bacon on top. Serve at once.