1/2 c. chopped onion
2 tbsp. butter
2 (8 oz.) cans tomato soup
1/2 c. brown sugar
1/3 c. Worcestershire sauce
1 tbsp. mustard
1 tbsp. vinegar

Saute' onion in butter until tender. Stir in remaining ingredients. Simmer for 5 minutes, stirring often. Makes 3 1/2 cups.