Found this on Cooks Illustrated website when looking for a sauce for the Apple-Glazed BBQ Ribs recipe that I'm learning. Frankly I thought this turned out to be pretty darn good.
Ingredients
1 medium onion, peeled and quartered
1/4 cup water
1 cup ketchup
5 tbls molasses
2 tbls cider vinegar
2 tbls Worcestershire sauce
2 tbls Dijon mustard
1 1/2 tsps liquid smoke (optional; first time I made it was strong, might try 1 tsp)
1 tsp hot pepper sauce
1/4 tsp ground black pepper
2 tbls vegetable oil
1 medium clove garlic minced or pressed (about 1 tsp)
1 tsp chili powder
1/4 tsp cayenne pepper
INSTRUCTIONS
Process the onion with the water in a food processor until pureed and the mixture resembles slush, about 30 seconds. Strain the mixture through a fine-mesh strainer into a liquid measuring cup, pressing on the solids with a rubber spatula to obtain 1/2 cup juice. Discard the solids.
Whisk the onion juice, ketchup, molasses, vinegar, Worcestershire, mustard, liquid smoke (if using), hot pepper sauce, and black pepper together in a medium bowl.
Heat the oil in a large nonreactive saucepan over medium heat until shimmering but not smoking. Add the garlic, chili powder, and cayenne and cook until fragrant, about 30 seconds. Whisk in the ketchup mixture and bring to a boil; reduce the heat to medium-low and simmer gently, uncovered, until the flavors meld and the sauce is thickened, about 25 minutes. Cool the sauce to room temperature before using. (The sauce can be refrigerated in an airtight container for up to 1 week.)
Notes: recipe calls for 1-1/2 tsps liquid smoke, that was rather strong. Also, when I make this for the Apple-Glazed BBQ Ribs recipe, I cook the sauce down fairly thick. I then use some of the degreased pan-drippings from the ribs to thin the sauce back out again. This adds some of the apple-flavor to the sauce.