Over medium heat, in a medium saucepan, cook bacon until crispy. Reserve about 1 Tbsp. bacon grease in the pan, and transfer cooked bacon to a paper towel-lined plate.
Lower the heat to medium-low. Sauté onion & shallots, stirring frequently, until they are caramelized, roughly 15 minutes.
Stir in the remaining ingredients, and put the bacon back into the pan too. Cook until the liquid has reduced, the mixture has thickened, and the onions are jammy, 7-10 minutes.
Cool the jam before pouring it into a jar. Serve how you’d like!