Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   1      medium        onion -- chopped fine
   4      pounds        roast beef or round steak
     1/2  cup           chopped green bell pepper
   1      cup           ketchup
   1      teaspoon      prepared mustard
     1/4  cup           vinegar
     1/2  cup           firmly packed brown sugar
   2      tablespoons   Worcestershire sauce
                        salt and pepper -- to taste
   1      cup           water

Preparation:

Combine all ingredients (except meat) and stir. Cut meat into bite size cubes. Add meat to sauce mixture. Place in crock-pot on low setting for 6-8 hours with lid on. For thicker sauce, keep lid on for 4 hours and take lid off for 2 hours.