In a large skillet or saucepan over medium heat, combine the bourbon whiskey, minced garlic, and diced onion. Simmer until the onions become translucent, approximately 10 minutes. The whiskey will reduce slightly and infuse the aromatics with its flavor.

Add the ketchup, apple cider vinegar, and Worcestershire sauce to the skillet. Stir thoroughly to combine all ingredients into a smooth base.

Mix in the brown sugar and molasses, stirring until completely dissolved. This creates the sweet foundation that balances the whiskey's bite.

Add the liquid smoke (if using), dijon mustard, paprika, black pepper, cayenne pepper, and salt. Stir well to incorporate all seasonings evenly throughout the sauce.

Reduce heat to low and simmer the sauce uncovered for about 20-25 minutes, stirring occasionally to prevent sticking. The sauce will thicken as it reduces.

Remove from heat and allow the sauce to cool slightly. For a smoother texture, you can blend the sauce using an immersion blender or transfer to a standard blender (be careful with hot liquids).

Let the sauce cool completely before transferring to airtight containers or mason jars.