In a saucepan over medium heat, add the bourbon and shallots. Simmer for 2-3 minutes to mellow the alcohol.
Add the apple cider, maple syrup, brown sugar, apple cider vinegar, Dijon, Worcestershire, garlic, cinnamon, allspice, and thyme.
Bring to a gentle simmer.
Reduce heat and cook for approximately 20-25 minutes, stirring occasionally, until reduced by about one-third and thick enough to coat the back of a spoon.
Remove the thyme sprigs.
Whisk in the butter until glossy.
Taste and adjust with a little more vinegar if you want additional acidity, or maple syrup for sweetness.
Set aside approximately half the glaze for serving. Keep the remainder for brushing onto the ribs.