Cut 1/2 an onion into quarters. With the flat end of a knife, crush the garlic cloves.
4 cloves garlic, 1/2 onion
Combine bourbon, garlic, and onion in a saucepan and heat until simmering. Simmer for 10 minutes.
1 cup bourbon
Mix remaining ingredients until well-blended, then add to the bourbon. Simmer another 20 minutes or longer. Whisk periodically to keep it smooth and incorporate onion and garlic.
2 cups ketchup, 1/2 cup brown sugar, 1/3 cup apple cider vinegar, 1/4 cup tomato paste, 1/4 cup worcestershire sauce, 1-1/2 tbsp liquid smoke, 1 tbsp spicy brown mustard, 1 tbsp all-purpose seasoning
Remove onion and garlic and let the sauce cool until it can be stored in an airtight container or squeeze bottle. Store in the refrigerator.
Notes
Don't worry about using a high-end bourbon. Grab some Jim Beam and save the top-shelf stuff for sipping. At the end, you have a few options:
Discard onion and garlic for a smooth sauce
Remove onion and garlic and run them through a food processor, then add back in for texture
Remove onion and garlic and run them through the food processor, then strain through a mesh strainer to get the flavor without adding texture