INSTRUCTIONS
1. In a heavy saucepan over medium heat, warm the olive oil and melt the butter. Add the onion and water and season with salt and pepper. Cover and cook, stirring occasionally, until the onion is very soft, 5 to 7 minutes. Stir in the brown sugar, chili powder and cumin until the onions are coated. Stir in the ketchup, barbecue sauce, molasses and Worcestershire sauce and simmer for 15 minutes. Pour the sauce into a blender and process until smooth. Taste and adjust the seasonings.
2. Use immediately, or cover tightly and refrigerate for up to 1 week.