Preheat your smoker to 250°F using oak or hickory wood.
In a small bowl, whisk together the Kosher salt, coarse black pepper, smoked paprika, dark brown sugar, garlic powder, and onion powder to create the rub.
Remove the silver skin membrane from the back of the beef ribs using a butter knife and paper towel.
Apply the seasoning mixture generously to all sides of the ribs, pressing it gently into the meat.
Place the ribs in the smoker and cook undisturbed for 3 hours to set the bark.
Spritz the ribs with water or beef broth hourly after the first 3 hours, cooking until the internal temperature reaches 203°F (about 3 more hours).
Remove the ribs from the smoker and let them rest for 45 minutes before slicing.