Pat the pork ribs dry with paper towels. If there's a thin, papery membrane on the concave side of the ribs, remove it. To do this, use a knife to lift an edge of the membrane from one end, then grip it with a paper towel and pull it off. This step is optional but helps with tenderness.

Cut the full rack of ribs into 2-3 bone sections. This makes them easier to handle and fit into the slow cooker.

In a small mixing bowl, combine the brown sugar, smoked paprika, garlic powder, onion powder, salt, black pepper, and cayenne pepper (if using). Mix well to create your dry rub.

Generously sprinkle and rub the spice mixture all over the rib sections, ensuring they are well coated on all sides.

In a separate bowl, whisk together 1 cup of the BBQ sauce, apple cider vinegar, Worcestershire sauce, and water. Set aside the remaining 1/2 cup of BBQ sauce for later.

Arrange the seasoned rib sections in your 6-quart (or larger) slow cooker. You can stack them if necessary, but try to ensure as much surface area as possible is exposed to the sauce.

Pour the prepared liquid sauce mixture over the ribs in the slow cooker.

Cover and cook on low for 7-8 hours or on high for 3.5-4 hours, until the ribs are very tender and easily pull away from the bone.

Carefully remove the cooked ribs from the slow cooker with tongs and place them on a foil-lined baking sheet. Be gentle, as they will be very tender.

Preheat your broiler to high. Baste the ribs generously with the reserved 1/2 cup of BBQ sauce.

Broil for 3-5 minutes, watching closely to prevent burning, until the sauce is caramelized and bubbly, and the edges of the ribs are slightly crisped. This step is optional but adds a great texture and finish.

Serve hot with extra BBQ sauce on the side, if desired. Enjoy!