Heat a large skillet over medium high heat and add the chopped bacon. Cook the bacon, stirring frequently, until it is almost crispy and cooked through.
Remove the bacon and some of the bacon grease from the skillet, leaving about 1 ½ tablespoons of bacon grease in the skillet.
Return the skillet to medium heat and add the apple and onion. Saute until tender, about 10 minutes.
Add the apple cider vinegar, maple syrup, brown sugar, balsamic vinegar, and cooked bacon to the pan. Simmer for approximately one hour, until the sauce has reduced and everything is deeply caramelized.
Remove the skillet from the heat and enjoy hot or cold, as desired.
Substitute coconut sugar for the brown sugar for a refined sugar-free jam.
Pairs well with crostini and brie for a decadent appetizer.