Start by taking the 1lb of thick-cut bacon and cutting it into ½ inch slices.
Next, throw them into a frying pan on medium heat and let the fat start to render down. Don’t worry about how evenly they are cooking or if every piece is separated at this stage. Let them cook slowly, and they will start to separate themselves.
Cover the pan and turn the heat up to medium-high and let them cook for about 10 minutes. Keep agitating them every few minutes and fry them until they are mostly cooked - but not completely crispy, as we’ll still be cooking them further. The main goal here is mostly just to render the fat down.
Pour most of the cooked bacon grease into a suitable container, leaving about one tablespoon’s worth in the pan. If that’s tough to gauge, pour it all out and re-add one tablespoon back into the pan.
Next, we add the onions to the pan and cook them for 8-10 minutes on medium-high. Once that’s finished, turn the temperature down to low.
To this, we’ll add ½ cup of brown sugar and stir it in thoroughly. Continue cooking this mixture for about 20 minutes to render the cooked bacon and caramelized onions. Now we add the rest of the ingredients, which include the bacon grease we decanted earlier, the pre-brewed strong coffee, and a cup of water. Essentially everything bar the vinegar.
Continue cooking all of this on medium-low heat for about 30 minutes until the consistency turns into that of jam. The onions should be thick and caramelized, and the bacon should be fully cooked.
Now we can remove it from the heat and add the balsamic vinegar to taste. We recommend about one tablespoon. You can also add a little salt at this stage too if that’s something you like. Extra tip: If you prefer more of that sticky/gooey kind of jam, you can also add some fig jam here. You need to stir it in thoroughly, and it’ll thicken the jam right up and make it taste sweeter.
Allow the bacon onion jam to come up to room temperature before serving. Alternatively, it can be refrigerated for up to a week.