In a heavy bottomed medium saucepan, heat the oil over medium heat. Add the onion and the garlic and cook, stirring often, until the onion is golden, about 8 minutes.
Stir in the remaining ingredients and bring to a boil. Reduce the heat to low. Simmer, stirring often, until slightly thickened, about 40 minutes. Cool completely. (To store, refrigerate in an airtight container for up to 1 week)
Brush onto food during the last 10 minutes of grilling.
CLASSIC BBQ SAUCE