Cook bacon over medium heat, allowing it to get crispy and for almost all the fat to cook away. Lay on paper towels and blot to remove excess oil. Crumble when cool.
Drain all but 2 tablespoons of the bacon grease from pan and discard.
Put minced shallots and onions in pan with bacon grease. Cook on MH heat 8-10 minutes, stirring frequently.
Add garlic and cook 1 more minute.
Add bourbon, syrup, and spices. Bring to a boil for 3 minutes, stirring to scrape pan.
Add vinegar and brown sugar. Continue to stir for 3 minutes.
Add crumbled bacon back to pan. Reduce heat to low and simmer 10 minutes.
Remove from heat and allow to cool. Transfer to jars and refrigerate up to 2 weeks.