Chop the bacon and cook it in a large skillet or Dutch oven over medium-high heat until crispy, stirring occasionally, about 8 minutes.

Use a slotted spoon to transfer the cooked bacon to a bowl and set it aside. Discard the majority of the bacon fat, leaving about 1 to 2 tablespoons to cook the onions. Note: Don't leave too much bacon grease or it will solidify in the jam in the refrigerator.

Transfer the sliced onions to the skillet and sprinkle liberally with sea salt. Sauté the onions for 10 minutes on high heat until they begin to turn golden-brown, then reduce the heat to medium heat and continue cooking for another 20 to 30 minutes, until the onions are very soft, caramelized, and golden-brown. Note: I cover the skillet to get the cooking process going faster and remove the lid from time to time to stir the onions well. If at any time the edges of the onions begin to turn too dark, lower the heat slightly and add a few tablespoons of water to deglaze the pan. 

Add the garlic, reserved bacon, coconut sugar, pure maple syrup, and balsamic vinegar and continue cooking, stirring occasionally, until much of the liquid has evaporated and you’re left with a thick, sticky soft mixture, about another 10 minutes. 

Transfer the bacon jam to an airtight container such as a mason jar and refrigerate until completely chilled. Serve the jam on crackers with cheese or on toasted bread with cheese or butter.