Slice onions and chop bacon into the proper size*

Cook the bacon starting in a large cold skillet over medium heat until bacon is crispy and fat is rendered

Remove bacon from skillet along with all but 1 tablespoon of bacon fat

Add onion to pan and sprinkle with salt to help remove water from onion as they cook

Cook onion over medium low heat stirring often and scraping the bottom of the pan to deglaze until onions are caramelized

Once onions are caramelized, add bacon back into skillet then stir in brown sugar.

Once brown sugar is incorporated, stir in water and cook over medium high heat until the water is reduced and the mixture is syrupy and jam-like

Stir in balsamic vinegar. Serve over sandwiches or burgers

To store, let jam cool to room temperature, then store in an air tight container in the refrigerator for up to 2 weeks

To serve after storage, reheat desired amount on stove top or in a separate container in the microwave until back to jam consistency as this will seize up slightly in the fridge