Spray a 6-quart or larger slow cooker with nonstick spray.
Add the ribs in an even layer.( wash and pat dry. Remove white film on back of ribs to allow better absorption of flavors )
In a small bowl or large measuring cup, stir together the ketchup, brown sugar, apple cider vinegar, hot sauce, chili powder, garlic powder, salt, pepper and rosemary.
Pour half of the sauce over the ribs, then cover the sauce bowl and save the rest in the refrigerator.
Cover the ribs and cook on low for 8 hours or on high for 4-5 hours, until they are cooked and ultra tender.
Serve with the remaining saved sauce or you can make it dry by broiling it for 3-4 minutes in the oven after slow cooking it.
Pairs well with baked or mash potatoes or even creamed spinach!