Instructions:

Firehouse Jack's Mustard BBQ Sauce

Source: Jack McDavid, owner of Jack's Firehouse in Philadelphia - From Barbecue Bible by Steven Raichlen

3/4 cup distilled white vinegar
1/2 cup beef or chicken broth
1/2 cup finely minced onion
1/4 cup seeded minced jalapeno chilies
1/2 cup Dijon mustard
1/4 cup honey mustard
1/4 cup corn syrup
2 tablespoons molasses
1/2 teaspoon black pepper
1/2 teaspoon coarse salt
1/4 teaspoon cayenne pepper

Combine all ingredients in a heavy nonreactive saucepan over high heat and bring to a boil. Reduce heat and simmer until thick.