cayenne powder to taste (I recommend 1/4 teaspoon)
In a small to medium saucepan, combine all ingredients with a spoon or whisk. Bring to a simmer over medium-high heat.
When simmering, reduce to medium to continue cooking at a low simmer. Continue to cook for 10 minutes, stirring frequently, until thickened.
Use immediately or cool and store in a covered container in the fridge.
You can use light brown sugar instead of dark brown sugar if that's all you have. You could add a tablespoon or two of molasses in this case.
Don't have chipotle chili powder or don't want to buy it just for this recipe? Substitute it with regular chili powder. If you do this, I'd consider using smoked paprika instead of sweet paprika so you still get the smokiness that the chipotle chili powder adds.
Try using smoked paprika instead of regular sweet paprika for an extra smoky bbq sauce.
If you want to make this with no ketchup, you could substitute with all tomato sauce. You might need to add some extra vinegar and/or sugar to compensate for the flavor of the ketchup...let your taste buds be your guide.