Combine brown sugar, vinegar, and mustard in a medium mixing bowl, mixing to form a paste; stir well, and set aside.
Place bacon in a lightly greased roasting pan; coat with brown sugar paste. Cover tightly with aluminum foil, and refrigerate overnight.
Pour wine over bacon; cover and bake at 350° for 1 1/2 hours. Uncover and bake an additional 30 minutes or until bacon has browned. Remove bacon to a warm serving platter; let stand 10 minutes before slicing. Slice and serve with Port Wine Sauce.