Trim excess fat from brisket. In a roasting pan, place onion slices, lemon slices and garlic. Lay brisket on top of vegetables.

Mix together port, brown sugar, and herbs; stir until sugar dissolves, then pour evenly over brisket. Sprinkle brisket with pepper and cover roasting pan tightly with foil. Bake in a 300 degree F oven until brisket is very tender when pierced, about four hours. Brisket can be cooled and refrigerated at this point until one is ready for the finishing.

When brisket is tender, uncover pan and return it to the oven (raise temperature to 450 degrees F) to brown the meat slightly, about 20 minutes. Remove brisket from pan.

Skim off fat from pan juices and put in sauce pan. Boil juices and vegetables, uncovered, stirring often. As mixture thickens, reduce heat to medium and stir constantly; cook until thick and shiny, and reduced to about 1-3/4 cups (20-30 minutes). Add salt to taste. To serve, slice across the grain. Spoon marmalade over brisket. Garnish with lemon "bows" and chopped parsley if desired.