Trim fat from ribs. Place ribs in a 4- or 5-quart slow cooker. In a medium bowl, combine barbecue sauce, onion, celery, mustard, brown sugar, Worcestershire sauce, garlic, and thyme. Pour sauce mixture over ribs in cooker.
Amazing Dry Rub Oven Roasted 'Fall off the Bone' Ribs and easy homemade BBQ Sauce with a secret ingredient that takes it over the top!