Remove the membrane from the back of the ribs (look for the flap at the corner of the rack and pull it slowly off). Rinse and pat completely dry with paper towels.
In a small bowl, mix together the sugar and seasonings. Use your fingers to rub and spread the seasonings all over the racks, front, back and sides.
Tightly wrap the ribs (together or separate) in aluminum foil. Place the packet onto a large rimmed baking sheet. Bake them for 2½ hours.
Sauce:
Whisk together all of the ingredients.
Open the foil packet and carefully drain the liquids from the pan.
Brush the sauce all over the tops of the ribs and BROIL them for another 3-4 minutes, until they start to caramelize. Remove them from the oven and let them rest for 5 minutes prior to slicing.
Notes
You can also use store bought BBQ sauce.When draining the liquids from the pan, I would remove the racks and transfer them to a cutting board and then pour out the liquids.