Start by dicing your bacon and adding it to a skillet over medium heat. Cook until crispy, then use a slotted spoon to transfer the bacon to a paper towel-lined plate. Reserve 2 tablespoons of bacon fat in the pan.
Add your diced onion, garlic, brown sugar, syrup, vinegar, salt, and pepper to the skillet.
Tip: You can sauté the onions first if you want extra caramelization, or simply boil everything together.
Stirring frequently, bring the mixture to a boil, then continue to boil for another 10 minutes before reducing to a simmer.
Add cooked bacon back in and simmer for 1 to 2 hours, stirring occasionally, until the jam thickens. It will continue to thicken as it cools.
Spoon the jam into two 6-oz mason jars, let it cool, and store in the fridge.