01 - Remove the membrane from the back of the ribs, if present, to ensure better tenderness and spice penetration.
02 - In a small bowl, combine the brown sugar, paprika, smoked paprika, garlic powder, onion powder, black pepper, salt, and cayenne pepper until evenly blended.
03 - Rub the spice mixture generously over both sides of the ribs. Allow the seasoned ribs to rest at room temperature for 20 minutes.
04 - Preheat a charcoal or gas grill to medium indirect heat, approximately 285-320°F (140-160°C).
05 - Wrap each rack of ribs tightly in aluminum foil, adding a splash of apple cider vinegar inside each packet. Place the foil-wrapped ribs on the grill, cover, and cook for 1½ hours, turning occasionally.
06 - Carefully remove the ribs from the foil and brush generously with barbecue sauce on all sides.
07 - Return the unwrapped ribs to the grill over direct medium heat. Grill for 10-15 minutes, turning and basting with additional sauce until caramelized and slightly charred.
08 - Let the ribs rest for 5 minutes before slicing between the bones and serving.