Preheat your smoker to 225°F. If using a charcoal grill, set it up for indirect heat.
In a small bowl, mix together the kosher salt, black pepper, garlic powder, onion powder, smoked paprika, and cayenne pepper.
Pat the beef ribs dry with paper towels and rub the spice mixture all over the ribs, ensuring they are evenly coated.
Place the ribs in the smoker bone side down. Smoke for about 5-6 hours, or until the internal temperature reaches 195°F to 203°F for tender meat.
During the last hour of cooking, brush the ribs with beef broth every 20 minutes to keep them moist.
In the last 30 minutes, apply a generous layer of BBQ sauce to the ribs and allow it to caramelize.
Once done, remove the ribs from the smoker and let them rest for 15-20 minutes before slicing.