In a bowl, combine all the ingredients. Set aside.
On a work surface, use paper towels to peel away the white membrane (silverskin) on the back of the ribs. Place the ribs on
a baking sheet and rub both sides generously with the spice rub. Cover and refrigerate for at least 1 hour, or overnight.
With the rack in the middle position of the oven, preheat the oven to 325°F (170°C).
Wrap the ribs, two racks at a time, in heavy-duty aluminum foil. Transfer to a baking sheet. Bake for about 2 hours, or until the meat is tender.
Meanwhile, in a small saucepan over medium-high heat, cook the spices in the butter for 1 minute. Add the remaining ingredients, bring to a boil and simmer over low heat for about 5 minutes or until the sauce becomes syrupy. Season with salt and pepper.
Preheat the grill, setting the burners to medium. Oil the grate.
Remove the ribs from the foil and grill for 4 to 5 minutes
on each side, brushing with half of the barbecue sauce. Serve with the remaining sauce.