Preheat oven to 300° and line a baking sheet with aluminum foil. If your ribs have a thin membrane over the bones on the backside, remove by carefully sliding a knife under membrane and then peel it away.

In a small bowl stir together brown sugar, salt, garlic powder, pepper, paprika, mustard powder, and cayenne. Rub mixture all over ribs and place on prepared baking sheet. Cover with foil and bake until very tender, 2 hours.

Meanwhile make barbecue sauce: In a medium saucepan over medium heat, combine all sauce ingredients together. Bring to a boil, then reduce heat and let simmer, stirring occasionally, until thickened, 1 hour.

Turn oven to broil. Remove foil from ribs and brush both sides with barbecue sauce. Broil until sauce just starts to caramelize, 2 to 4 minutes.