1 flat cut brisket (med.-lg.)
2 med. yellow onions, sliced thin
2 pkgs. onion soup

Arrange heavy duty foil in bottom of roasting pan, enough to wrap around brisket. Arrange onion on foil. Set brisket on top and sprinkle dry onion soup on top. Seal tight with foil. Roast until meat is fork tender, about 5 hours at 250 degrees. Do not peek at meat before. Remove from oven and let stand sealed for 1 hour before serving.