Wipe meat with wet cloth and season well with salt & pepper and the ginger. Dredge with flour and place in roasting pan in a hot oven (400-F) until meat is brown. Reduce heat to 350-F and roast for three hours. Add 1 cup hot water and the sliced onions after the first hour and baste every 15 minutes. When roast is finished, remove to hot platter and to the liquid in the pan add 2 Tbsp flour, stirring until blended. Pour in 1 1/2 cups of water and cook, stirring constantly, until mixture is thick. Serve as a gravy.