Preheat oven to 275°F. Line a large rimmed baking sheet with foil.
Remove the thin white membrane from the back of the ribs. Run a butter knife under the membrane to loosen, then use a paper towel to grip and pull it off.
Place ribs on the foil-lined baking sheet, meaty side up.
Combine paprika, garlic powder, onion powder, chili powder, salt, and pepper in a small bowl. Rub mixture all over the meaty side of the ribs.
Cover ribs tightly by wrapping a few sheets of foil around the baking sheet. Alternatively, wrap each rack individually.
Bake for 3 to 3½ hours, until ribs are very tender. Unwrap and pull off a small piece of meat to check doneness.
Remove from oven. Preheat broiler to low setting. Remove and discard the foil covering. Brush ribs generously with BBQ sauce.
Broil for 2 to 4 minutes, until BBQ sauce just starts to caramelize. Watch carefully to prevent burning.
Let rest for 5 minutes before serving.
Notes
Alternative cuts: Spare ribs, St. Louis-style ribs, or country-style ribs also work with similar cook times.
Reheating: Place ribs in a baking dish, brush with BBQ sauce, cover with foil, and reheat at 250°F for 15 to 30 minutes until internal temp reaches 145°F.