Remove the membrane from the back of the ribs and cut each rack of ribs in half so that they fit easily in the slow cooker.

In a small bowl, whisk together the paprika, brown sugar substitute, salt, pepper, garlic powder, onion powder, and parsley.

Sprinkle the dry rub over each side of the ribs and use your hands to press it into the meat.

Add the apple cider vinegar to the bottom of a slow cooker along with 2 tablespoons of water. Place the ribs in the slow cooker.

Cook, covered, on high for 4 hours or low for 8 hours.

When ribs are tender but not falling apart, carefully remove them from the slow cooker to a large baking sheet. Brush with barbecue sauce.

Place under the broiler until the sauce has thickened and begun to caramelize, about 5 minutes. 

Let rest for 5 minutes before serving.