Sweet And Sour Beef

2 Tbsp. butter
3/4 c. ketchup
1 medium onion, chopped fine 1 or 2 tsp. vinegar
2 Tbsp. prepared mustard
1 Ib. London Broil
1 Tbsp. Worcestershire sauce
1 tsp. salt
2 Tbsp. brown sugar

Brown meat and onion in oleo. Mix the remaining ingredients. 

Put meat and onion in crock pot. Pour sauce over meat. Cook on LOW all day.