Divide Johnston’s bacon between 2 skillets and cook over medium-high heat. Stir frequently until bacon is lightly brown and starting to crisp.
Place bacon on paper towels to drain. Discard fat from one skillet. Pour off all but one tablespoon of fat from the remaining skillet.
Add onions and garlic. Stir frequently until onions are softened. Add vinegar, brown sugar, maple syrup, coffee, and bourbon.
Bring to a boil and cook for 2 minutes. Add bacon and stir to combine. Cook on low, uncovered, until liquid has reduced and thickened slightly (3-4 hours).
Transfer mixture to food processor and pulse until coarsely chopped. Let cool, transfer to air tight jars and store in refrigerator up to 1 month. Makes 3 cups.