Preheat your oven to 275°F.
Mix together the brown sugar, paprika, black pepper, salt, chili powder, garlic powder, onion powder, and cayenne pepper to make the dry rub.
Rub the spice mixture all over the ribs, ensuring every part is covered.
Wrap each rack of ribs in two layers of foil. Make sure they're wrapped tightly.
Bake the ribs in the preheated oven for 2.5-3 hours, or until the meat is tender and falling off the bone.
Unwrap the ribs carefully (watch out for hot steam) and brush them with your favorite barbecue sauce.
Broil the ribs for about 5 minutes, or until the sauce is bubbly and caramelized.
Allow the ribs to rest for a few minutes before cutting into individual servings.