1 (4 lb.) boneless beef roast

Remove as much fat as possible, cut into large chunks.

1 chopped onion
21 oz. ketchup
3 tbsp. mustard
9 tbsp. white vinegar
9 tbsp. sugar
1 1/2 tbsp. Worcestershire sauce

Cook beef roast in slow cooker with enough water to cover. Cook 12-15 hours or until roast shreds into small pieces easily. Remove as much juice from cooker as possible - shred (with a fork) meat into bite size pieces.

Mix remaining ingredients together. Pour over meat. Slow cook on low for at least 1 hour or until ready to eat.

Serve on hamburger buns.

Note: Great party food - extras freeze well. More or less sauce can be made and used, depending on amount of meat used.