Whisk all the ingredients together in a large saucepan and bring to a boil over medium-high heat. Reduce heat to maintain a simmer and cook, stirring occasionally, until reduced by about half or to desired thickness, about 1 hour.
Cool completely before transferring to an airtight container and storing in the refrigerator.
Cook's Note: Use the BBQ sauce within 1 week or freeze for up to 6 months.
Recipe courtesy Claire Robinson