2 (16 oz.) bottles ketchup
1/4 c. prepared mustard
6 tbsp. Worcestershire sauce
4 tbsp. vinegar
3/4 c. onion, finely chopped
6 tbsp. brown sugar
6 tbsp. melted butter
Juice and grated rind of 3 lemons

Mix all ingredients together in saucepan. Simmer slowly, stirring frequently, until onion is soft. Remove from heat and let sit 30 minutes. Strain before using if desired. Brush on chicken or pork while cooking or use as a side dish.