In a crockpot, combine the following: 

1 1/2 pounds lean stew beef
1 1/2 pounds lean pork cubes
1 cup finely chopped onion
2 cups finely chopped green bell pepper

Combine the following ingredients:

1 (6 ounce) can tomato paste
1/2 cup packed brown sugar
1/4 cup cider vinegar
1 tablespoon chili powder
1 teaspoon salt
2 teaspoons Worcestershire sauce
1 teaspoon dry mustard

Blend all of these ingredients well and add to the crockpot. Stir into the meat, onion and pepper mixture. Cover and cook on HIGH for 8 hours. Stir to shred meat before serving on buttered rolls or pita bread.

NOTE: If you do not have a crockpot, you can simmer this mixture on top of the stove. Use a very heavy Dutch oven with a tight-fitting lid.

This may also be served over rice rather than using rolls, if desired. Leftovers freeze great.