Combine cauliflower, broth, celery, onion, salt and pepper in crock-pot slow cooker
Cover and cook on low 7 - 8 hours or on high 3 - 4 hours
Pour cauliflower mixture into food processer or blender or use a submersion blender and process until smooth
Add milk and Worcestershire sauce; process until blended
Add back to crock-pot; cover and cook on high 15- 20 minutes or until heated through