1. Prepare the Ribs:

• Spread the BBQ rub (store-bought or homemade) generously over the ribs. Massage it in with your hands, ensuring even coverage on all sides.
• Wrap the ribs in foil or plastic wrap, place them on a baking sheet, and refrigerate overnight to allow the flavors to penetrate.

2. Make the BBQ Rub (if using homemade):

• In a small bowl, combine the brown sugar, smoked paprika, chili powder, garlic powder, onion powder, black pepper, salt, and cayenne pepper (if using). Mix thoroughly until well combined.

3. Make the Honey Bourbon BBQ Sauce:

• Place the sliced onion, minced garlic, ketchup, bourbon, honey, apple cider vinegar, Worcestershire sauce, Dijon mustard, and salt into a medium saucepan over medium heat.
• Cook the sauce, stirring occasionally, until it has reduced by about ¼, which should take around 30 minutes.
• Let the sauce cool slightly, then transfer it to a high-powered blender. Blend until the sauce is smooth and well combined.

4. Cook the Spare Ribs:

• Place the prepared spare ribs in the slow cooker, ensuring they fit comfortably.
• Pour about half of the honey bourbon BBQ sauce over the ribs, spreading it evenly.
• Cover the slow cooker and cook on low for 8-9 hours, or on high for 4-5 hours, until the ribs are tender and cooked through.

5. Finish the Ribs in the Oven:

• Preheat your oven to 400°F (200°C).
• Carefully remove the ribs from the slow cooker and place them on a foil-lined baking sheet for easy cleanup.
• Slather the ribs with more of the BBQ sauce and place them in the preheated oven.
• Cook for 10-15 minutes, or until the ribs develop a slightly crispy texture on the edges.

6. Serve:

• Serve the ribs immediately with the remaining BBQ sauce on the side for dipping.