This barbecue sauce is so darn good that it will be a permanent condiment in your refrigerator. Make an extra batch, and store in an airtight container up to 3 weeks.
Melt butter with oil in a large Dutch oven over medium heat.
Add onion and next 3 ingredients, and sauté 5 to 6 minutes or until onion is tender.
Stir in brown sugar and remaining ingredients; bring to a boil. Reduce heat to medium-low, and simmer 10 minutes. Pour mixture through a wire-mesh strainer into a bowl, discarding solids.