Combine the brown sugar, chili powder, salt, black pepper, oregano, cayenne, garlic powder and onion powder in a small bowl and rub the mixture onto both sides of the ribs. Cover and refrigerate for 1 hour, or up to overnight.

Preheat the oven to 250°F (120 C).

In a roasting pan, combine the broth and vinegar. Add the ribs to the pan, cover with foil and tightly seal. Bake for 2 1/2 hours. Remove the ribs from the pan and place them on a platter. Pour the liquid from the pan into a saucepan and bring to a boil. Lower the heat to a simmer and cook until it’s reduced by half. Add in the barbecue sauce.

Preheat an outdoor grill to medium-high. Put the ribs on the grill and cook for about 5 minutes on each side, until browned and slightly charred. Cut the ribs between the bones and toss them in a large bowl with the sauce. Serve hot.