1. Preheat your oven to 300°F (150°C).
2. Remove the membrane from the back of the ribs.
3. In a small bowl, mix together the brown sugar, paprika, salt, black pepper, garlic powder, and onion powder.
4. Rub the spice mixture all over the ribs.
5. Place the ribs on a baking sheet and cover with aluminum foil.
6. Bake in the preheated oven for 2.5 to 3 hours, or until the ribs are tender.
7. Remove the ribs from the oven and brush with barbecue sauce.
8. Place the ribs back in the oven, uncovered, and bake for an additional 30 minutes.
9. Remove from the oven and let rest for a few minutes before serving.