With Leftover Pot Roast

• To cook the roast and create your leftovers, brown the cut in an ovenproof pot on the stovetop for extra flavor. Then add braising liquid, such as beef broth or red wine, and aromatic vegetables, such as onions and garlic. Cover the pot and cook the roast in a low oven set at 275 or 300 degrees Fahrenheit. Cook the pot roast for three or four hours, or until it's very tender and falling apart. Serve the pot roast for one meal and reserve the leftovers for soup the next day.

From Scratch

• Another option is to start with a raw pot roast when making the soup. To go this route, cut the pot roast into 1-inch cubes. Heat oil in a heavy Dutch oven or stockpot, and brown the cubes well. Season the meat with salt, pepper, rosemary, thyme or any other desired seasonings. Add aromatic vegetables, such as onions, carrots and celery, and cover the ingredients in beef broth. Place a lid on the pot and simmer the soup for two or three hours, or until the vegetables and meat are tender. You can also cook this soup in a slow cooker set on the low setting for six to eight hours. Add the barley during the last 20 to 30 minutes of cooking.

The Cut to Choose

• Inexpensive, tough cuts, such as brisket, chuck, top round, bottom round or rump roast, work well for pot roast. These cuts have a lot of connective tissue, which melts into gelatin with long, slow cooking, adding tenderness and flavor. Cook the meat until it's falling apart and a meat thermometer inserted in the meat registers 180 to 190 F. This is higher than the temperature -- 145 F -- recommended by the U.S. Department of Agriculture as the minimum safe cooking temperature for beef, but it's necessary to get the falling-apart tenderness this soup needs.

Keeping It Safe

• No matter whether you use leftover beef or cook the beef directly with the soup, it's important to keep it safe. Refrigerate raw pot roast as soon as you get home at 40 F or below, and cook it within two or three days. Cover and refrigerate any leftovers -- pot roast or soap -- within two hours of serving.