Preheat the oven to 300°F (150°C).
Remove the membrane from the back of the ribs if it is still attached.
Pat the ribs dry with paper towels and brush both sides lightly with olive oil.
In a small bowl, combine brown sugar, smoked paprika, garlic powder, onion powder, chili powder, salt, black pepper, and cayenne pepper.
Rub the seasoning mixture generously over both sides of the ribs.
Place the ribs on a large baking sheet lined with foil or parchment paper.
Cover tightly with aluminum foil and bake for 2 1/2 to 3 hours until the ribs are tender.
Carefully remove the foil and brush the ribs generously with barbecue sauce.
Increase the oven temperature to 425°F (220°C) or switch to broil.
Cook for an additional 10 to 15 minutes until the sauce becomes sticky and caramelized.
Remove from the oven and let the ribs rest for 10 minutes.
Slice between the bones and serve with extra barbecue sauce.