Prepare the ribs: Carefully remove the thin membrane from the bone side of the rib rack. To do this, slide a knife under the membrane at one end of the rack to loosen it, then grip it with a paper towel and pull it off. If desired, cut the full rack into 2-3 smaller portions to fit more easily into your slow cooker.
Arrange ribs in slow cooker: Place the prepared ribs into the slow cooker. You can stand them on their sides or stack them if necessary to fit, ensuring an even distribution.
Add liquid and sauce: Pour the apple cider vinegar over the ribs. Then, generously spread your favorite BBQ sauce over all surfaces of the ribs, ensuring they are well coated.
Cook: Cover the slow cooker with its lid. Cook on the HIGH setting for 4 hours, or until the ribs are incredibly tender and easily pull away from the bone.
Optional finish (for crispy exterior): If you desire a caramelized, slightly crispy finish, carefully transfer the cooked ribs to a baking sheet lined with aluminum foil. Baste with additional BBQ sauce if desired. Broil on high for 3-5 minutes, watching very carefully to prevent burning, as BBQ sauce can quickly scorch.
Serve: Remove from the slow cooker or broiler (if applicable), let rest for a few minutes, then cut into individual ribs and serve immediately. These ribs pair wonderfully with coleslaw, corn on the cob, or baked beans.
Notes
For an extra layer of flavor, consider rubbing the ribs with a simple dry rub (like paprika, garlic powder, salt, and pepper) before adding the BBQ sauce. This recipe uses apple cider vinegar to help tenderize the meat and add a touch of tang, but you can substitute it with water or chicken broth if preferred. Leftover ribs can be stored in an airtight container in the refrigerator for up to 3-4 days and reheated gently.