Rinse inside of duckling; pat dry with paper towels. Skewer neck skin to back (see photo 2); tie legs to tail. Twist wing tips under back (see photo 4). Place duckling, breast side up, on a rack in a shallow roasting pan. Using a fork, prick skin generously.
Meanwhile, for sauce, pour enough boiling water over dried mushrooms to cover. Let stand for 30 minutes; drain. In a saucepan, cook mushrooms and onions in hot butter over medium heat about 15 minutes or until tender. Stir in sugar; cook and stir for 5 to 7 minutes or until vegetables are glazed. Stir in flour; cook and stir for 3 to 5 minutes more or until flour is browned. Add broth, tomato paste, savory, and Worcestershire sauce. Bring to boiling; reduce heat. Simmer, uncovered, for 10 to 15 minutes or until sauce is reduced to about 1-2/3 cups.
To carve duckling, if desired, remove the skin. Using a sharp knife, cut duckling along the backbone. Cut downward, cutting the meat from the ribs. Cut the wings and legs from the duckling. Slice breast meat. Serve with mushroom sauce. Makes 4 servings.