Mix together the brown sugar, paprika, salt, black pepper, garlic powder, onion podwer, onion flakes, and cayene pepper.
Rub into all sides of pork ribs. For best results, allow ribs to marinate for 2 hours or up to overnight.
Cover with foil tent and place on center rack of 250°F oven.
Bake for 2 1/2-3 hours. To make sure they are tender, test the temperature. We like to cook the ribs until they are about 180°F. If they are not tender, bake another 20 minutes and check again
When done, remove the ribs from oven and slather with your favorite BBQ sauce. You can return the dish to the oven (uncovered) for about 15 minutes or you can eat immediately.
Best served warm.