For the barbecue sauce, heat the olive oil in a large saucepan over medium-high heat.
Add the onion and cook for 4-5 minutes or until the onion is tender.
Add the coffee, ketchup, cider vinegar, dijon mustard, brown sugar and honey.
Whisk the ingredients together until smooth.
Season with salt, pepper and chipotle chili powder, then add the tomato paste and whisk to break up any clumps.
Bring the BBQ sauce to a boil and then reduce the heat to a simmer.
Simmer on low for 25-30 minutes.
Transfer the BBQ sauce to a large bowl to cool slightly.
