Remove the membrane from each rack of ribs.

Combine brown sugar, smoked paprika, garlic powder, onion powder, kosher salt, black pepper, and cayenne in a small bowl.

Coat all sides of each rib rack with the dry rub; let them sit at room temperature for 30 minutes.

Set up the grill for indirect heat, aiming for a temperature of 250 to 275 degrees Fahrenheit.

Place the rib racks on the unlit side of the grill, bone-side down.

Let the ribs cook undisturbed for the first two hours.

After two hours, wrap each rack tightly in aluminum foil with a splash of apple juice or water and cook for another 90 minutes.

In a small saucepan, combine barbecue sauce, honey, apple cider vinegar, soy sauce, butter, and garlic powder. Warm over low heat.

Unwrap the ribs and brush the glaze over both sides. Return them to the grill for the final 30 minutes.

Test for doneness by ensuring the meat has pulled back from the bones and the thermometer reads 195 to 203 degrees Fahrenheit.

Let the ribs rest for 5 to 10 minutes before serving.