Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2      tablespoons   unsalted butter
     1/2  medium        red onion -- finely diced
   1                    garlic clove -- finely diced
   6                    plum tomatoes -- coarsely
                        diced
     1/4  cup           ketchup
   2      tablespoons   Dijon mustard
   2      tablespoons   dark brown sugar
   1      tablespoon    honey
   1      teaspoon      cayenne
   1      tablespoon    ancho chile powder
   1      teaspoon      pasilla chile powder
   1      tablespoon    Worcestershire sauce

Preparation:

In a medium saucepan over medium heat, heat the butter and sweat the onion and garlic until translucent. Add the tomatoes and simmer for 15 minutes. Add the remaining ingredients and simmer for 20 minutes. Puree the mixture in a food processor, pour into a bowl, and allow to cool at room temperature. Will keep for 1 week or several months frozen.