1/3 c. onion, chopped
3 tbsp. butter
1 c. ketchup
1/3 c. vinegar or lemon juice
2 tbsp. brown sugar
1/2 c. water
2 tsp. mustard
1 tbsp. Worcestershire sauce
Pinch of salt

Saute butter and onion until onion is tender. Add other ingredients in order. Simmer, covered for 15 minutes.