Rinse ducks, pat dry, and remove excess fat. Arrange ducks, breast side up, several inches apart on a rack set over a large roasting pan.
In a bowl, combine Scotch, grated gingerroot, crushed garlic clove, grated orange peel, coriander, crushed peppercorns, soy sauce, honey, and brown sugar; mix well. Brush over the ducks every 30 minutes, for 2 1/2 hours.
Combine diced slices of white bread, chopped green onion, and parsley. Moisten the bread mixture with the remaining marinade. Spoon stuffing into the ducks.
Place ducks in a roasting pan and pour in beer. Roast the ducks on the rack in a preheated 350° F oven for 30 minutes. Tent with aluminum foil and roast for 30 minutes more. Discard the aluminum foil and roast for another 30 minutes, or until a meat thermometer registers 180*F.
Remove the stuffing and reserve the pan juices. Strain, skim the fat, and in a saucepan, bring the stock to a boil, simmering for 15 minutes. Stir in arrowroot powder dissolved in cold water. Cook over medium heat, being careful not to boil, until thick. Add salt and pepper. Serve with the duck.
Servings: 4