Pull neck skin of duckling to back; fasten with a skewer. Tie drumsticks to tail. Twist wing tips under back. Place bird, breast side up, on a rack in a shallow roasting pan. Prick skin. Insert a meat thermometer into breast (the bulb should not touch the bone).
Roast in a 350 degree F oven for 1-1/2 to 2 hours or until temperature reaches 180 degrees F. The drumsticks should move easily.
Meanwhile, pour enough boiling water over dried mushrooms to cover. Let stand for 30 minutes; drain.
In a saucepan cook mushrooms and onions in margarine or butter about 5 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 brown.
Add beef broth, tomato paste, herb, 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 duck, remove the skin, if desired. With a sharp knife, slice duck along the backbone. Slice downward, cutting meat from ribs. Remove wings and legs. Slice breast meat. Serve with sauce. Makes 6 servings.