1 beef brisket (4 to 5 pounds), trimmed of fat
1/4 C. all-purpose flour
1 packet onion soup mix (1.25 ounces)
1 can tomato soup (10.75 ounces)
1/4 tsp. black pepper
2 T. light brown sugar
2 T. red wine vinegar

Pat the brisket dry with paper towels. Place the flour in a shallow bowl. Dredge the brisket in the flour, then shake off the excess. Place the brisket in a 4½ -to 6-quart slow cooker. Place the onion soup mix, tomato soup, and pepper in a small bowl with ¼ C. of water and stir to combine. Pour this mixture over the brisket. Cover the cooker and cook the beef on high heat until it is quite tender, 6 hours. Remove the brisket from the cooker and place it on a platter. Cover it loosely with aluminum foil to keep it warm. Strain the liquid that is left in the cooker. Spoon off as much fat as possible or use a gravy separator to remove the fat from the liquid. Pour the strained and defatted liquid into a 2-quart saucepan and heat over medium heat. Add the brown sugar and vinegar and stir until the sauce heats through and the brown sugar melts. Slice the brisket, pour enough sauce over it to moisten it, then serve the remaining sauce on the side.