Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to use leftover roast [title] Make beef broth. [step] You can make a rich beef broth to have on its own or use the broth as a base for soups and stews. To make the broth, just saute large pieces of the leftover roast beef along with one diced onion.

Ending1: [substeps] Heat the beef broth in a slow cooker, or just put the onions in with it. Cook the beef broth in the slow cooker for four hours, stirring constantly. Ending2: Make sure you submerge the beef pieces in a quart of water to make the broth. Leave the meat in the broth for at least one hour and then take it out, rinse, and dry with a small amount of water and store it. Ending3: Once the onion is soft, add enough water to cover the meat. Bring this to a light boil and keep cooking until the water darkens. Ending4: Allow the beef broth to cook on low heat. [substeps] You can substitute sherry vinegar if you'd prefer a sweeter flavor.

Answer format: ending1/ending2/ending3/ending4