Preheat oven to 325° F.
Trim excess fat from brisket; sprinkle meat with pepper and salt. Place flour in a large oven-cooking bag and shake. Add brisket. Set the bag in a large roasting pan.
Add carrots, celery, onions, tomatoes, Marsala, Italian seasoning, and bay leaves to bag with brisket. Seal bag. Cut slits in top of bag.
Roast for 2 1/2 to 3 hours or until tender. Remove bay leaves. Slice meat across the grain into 1/4-inch thick slices. Skim fat from pan juices. Serve skimmed juices with meat.
Makes 12 main-dish servings.
To make ahead: Cool meat in bag; cover and chill overnight. To reheat, remove meat from bag; thinly slice. Place slices in a 3-quart rectangular baking dish. Skim fat from juices; pour over meat. Cover; heat in a 300° F oven for 50 minutes or until just heated through.
Servings: