Heat large skillet over medium heat and cook bacon until crisp. Transfer cooked bacon to pager towel lined plate to drain. Pour off bacon fat, leaving about 2 tablespoons in the skillet. (I also like to save the leftover bacon fat and put in a sealed container in the fridge to use for cooking)
Add onions and garlic and cook over medium heat until onions are translucent. (About 5-7 minutes) Add brown sugar, coffee, bourbon, apple cider vinegar, maple syrup, cumin, paprika and chili powder to skillet and bring to boil. (You can add ¼ cup of coffee and leave out bourbon if you don't want it) Stir in bacon pieces and remove from heat.
Add mixture to a slow cooker and cook, uncovered, on high setting for 4 hours. If you want a more jam like consistency, add to blender of food processor and pulse until desired consistency. (I don't do this step as I like the bigger bacon bits) Place in air tight container and put in fridge for up to four weeks.
Notes
Use Quality Bacon - When bacon is the start, don't skimp on it. You've got to go with the real deal bacon. I like to get thick-cut if possible.
Use Coffee and Bourbon - Like I mentioned above, if you don't want to have bourbon in your jam, you can just replace with additional coffee, but combined that add a great flavor profile to the jam. I mean bourbon and bacon are meant to go together.
Leave Slow Cooker Uncovered - It is key to leave the slow cooker uncovered to allow the liquid to evaporate at a slower rate than it would covered.
Don't Throw in Food Processor - I think bacon onion jam should have bits of bacon and onion throughout. If you throw in food processor or blender, you take that away.