Grab the largest skillet you have and add the olive oil, over low heat.  Add in the onions, about ¼ teaspoon of salt and cook until just tender, stirring frequently, about 15 minutes. 

Once the onions are soft, add in the chopped bacon.  Cook the bacon until it renders and is slightly crispy, stir.  I cooked mine on medium low for 40 minutes and then cranked the heat to medium and stirred constantly for another 5 minutes. 

Once the bacon is browned, add in the garlic and cook for about 1 minute.  Skim the fat off the top of the mixture, set it aside to cool then do what you want with it.  I tossed mine out, but some people like to keep it to cook with for another time.  Just strain out the yucky stuff and keep the rest. 

Add in the brown sugar, maple syrup, black pepper and apple cider vinegar.  Bring to a simmer, stirring frequently until it’s very dark and syrupy.  This will take anywhere between 15 – 20 minutes on LOW heat.  You do not want anything to burn.  Caramelize does not mean burning, it means sweet and soft.

Once the mixture is done cooking, serve it warm or cool completely and store in an airtight container in the refrigerator for up to 3 weeks.