Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/2  stick         butter
     1/4  cup           onion -- minced
   1 1/4  cups          cider vinegar
   1 1/4  cups          ketchup
     3/4  tablespoon    brown sugar
   1      teaspoon      Worcestershire sauce
     1/4  teaspoon      cayenne
                        salt and pepper

Preparation:

Sauté onion in butter. Add rest and simmer 30 min. Use on pork smoked with vinegar based mop.